The Thayer School of Engineering at Dartmouth College ENGS 190/ENGG 290 Final Report Ethanol as Fuel for Recreational Boats 9 March 2004 Sponsor/Advisor: Professor Charles Wyman Group Members: Erik Dambach, Adam Han, Brian Henthorn www.dartmouth.edu/~ethanolboat
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The Thayer School of Engineering at Dartmouth College
ENGS 190/ENGG 290 Final Report
Ethanol as Fuel for Recreational Boats
9 March 2004
Sponsor/Advisor: Professor Charles Wyman
Group Members:
Erik Dambach, Adam Han, Brian Henthorn
www.dartmouth.edu/~ethanolboat
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Table of Contents I. INTRODUCTION............................................................................................................................... 1
NEED STATEMENT ................................................................................................................................ 1 OBJECTIVES.......................................................................................................................................... 1
II. PROBLEM BACKGROUND............................................................................................................ 2 CASE AGAINST GASOLINE..................................................................................................................... 3
III. CASE FOR ETHANOL ................................................................................................................... 9 AQUATIC TOXICITY ANALYSIS ............................................................................................................ 13
IV. SPECIFIC FOCUS: CALIFORNIA .............................................................................................. 14 CASE FOR CALIFORNIA ....................................................................................................................... 14 ENVIRONMENTAL REGULATIONS......................................................................................................... 15 INFRASTRUCTURE FOR INTRODUCING ETHANOL AS A FUEL IN CALIFORNIA............................................ 18
V. HISTORY OF ETHANOL USE IN ENGINES............................................................................... 26 VI. ENGINE CHOICE JUSTIFICATION .......................................................................................... 29
THE FOUR-STROKE ENGINE ................................................................................................................ 31 VII. ENGINE MODIFICATIONS NECESSARY FOR ETHANOL OPERATION........................... 32 IX. MODIFICATIONS TO THE OUTBOARD ENGINE .................................................................. 35
X. GOAL ENGINE SPECIFICATIONS.............................................................................................. 44 XI. ENGINE TESTING........................................................................................................................ 44
EMISSIONS ......................................................................................................................................... 45 POWER ............................................................................................................................................... 49 EFFICIENCY WITH POWER ................................................................................................................... 52 COLD-START ...................................................................................................................................... 53 WEIGHT ............................................................................................................................................. 56 JET SIZE DETERMINATION................................................................................................................... 57
XII. ECONOMIC ANALYSIS OF ENGINE....................................................................................... 58 XIII. DISCUSSION OF SPECIFICATION RESULTS....................................................................... 60 XIV. MARKETABILITY..................................................................................................................... 61 XV. CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE STUDIES.............................. 62 XVI. ACKNOWLEDGEMENTS......................................................................................................... 64 XVII. LIST OF WORKS CITED......................................................................................................... 65
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Figures Figure 1. USA Ethanol Production Capacity..................................................................20 Figure 2. Original Main Jet............................................................................................36 Figure 3. Tubing in Fuel System....................................................................................38 Figure 4. Engine test set-up ...........................................................................................45 Figure 5. Hydrocarbon and NOx Emissions...................................................................48 Figure 6. CO and CO2 Emissions ...................................................................................49 Figure 7. Maximum Power ............................................................................................51 Figure 8. Full-Throttle Efficiency with Power ...............................................................53 Figure 9. EPA 2006 Emissions Limits .......................................................................... E1 Figure 10. CARB 2008 Emissions Limits for Marine Outboards and Personal.............. E1 Figure 11. Schematic for Ethanol Production.................................................................F3 Figure 12. US Average Ethanol and Corn Prices........................................................... G1 Figure 13. Fuel Ethanol Terminal Market Price (18 Month History) ............................. G2 Figure 14. Fuel Ethanol Terminal Market Price (10 Year History) ................................ G3 Figure 15. Fuel System Schematic................................................................................ L2 Figure 16. Carburetor Schematic .................................................................................. L3 Figure 17. Main Jet Side View .................................................................................... M1 Figure 18. Main Nozzle Front View ............................................................................ M1 Figure 19. Main Nozzle Side View.............................................................................. M1 Figure 20. Rubber Replacement Ethanol Compatibility Table....................................... N1 Figure 21. EDS for Main Jet of Carburetor ................................................................... O1 Figure 22. EDS for Fuel Pump ..................................................................................... O1 Figure 23. Hydrocarbon and NOx Emissions ................................................................ Q1 Figure 24. CO and CO2 Emissions ................................................................................ Q2 Figure 25. Power curve for Tohatsu 5 hp four-stroke outboard engine .......................... R1 Figure 26. Power at Mid-Throttle ..................................................................................S2 Figure 27. Maximum RPM values ................................................................................ T1 Figure 28. Mid-throttle Fuel Efficiency ........................................................................ U2
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Tables Table 1. Toxicity of Gasoline for an adult male. Onset of toxic effects from 10-48 hours
of ingestion..............................................................................................................5 Table 2.Feedstocks, fuel energy to fossil energy ratio and future potential of the
renewability of ethanol. .........................................................................................13 Table 3. EPA Exhaust Emission Standards ....................................................................16 Table 4. CARB Exhaust Emission Standards.................................................................17 Table 5. Projected Price Range for Ethanol Sale in California .......................................22 Table 6. Projected Price Range for Ethanol Sale in California at Marinas ......................25 Table 7. Cold start solutions matrix ...............................................................................42 Table 8. Engine Specifications ......................................................................................44 Table 9. Gasoline Emissions Data .................................................................................46 Table 10. Jet Diameter Matrix .......................................................................................57 Table 11. Engine modification costs with and without labor. .........................................59 Table 12. Specifications Assessment .............................................................................60 Table 13. Comparison of Ethanol Fuel Properties to Gasoline ...................................... A1 Table 14. Alternative Fuels for Gasoline Marine Engines Matrix.................................. C1 Table 15. Budgetary cost for each expense ................................................................... V1 Appendices Appendix A. Comparison of Ethanol Fuel Properties to Gasoline ................................. A1 Appendix B. Project Timetable..................................................................................... B1 Appendix C. Alternative Fuels for Gasoline Marine Engines ........................................ C1 Appendix D. Summary of Material Safety Data Sheets for Gasoline and Ethanol ......... D1 Appendix E. Emission Regulations Plots...................................................................... E1 Appendix F. Production of Ethanol................................................................................F1 Appendix G. Historical Cost of Ethanol........................................................................ G1 Appendix H. Ethanol Fuel Calculations ........................................................................ H1 Appendix I. Fuel induction method for engines by major manufacturers........................ I1 Appendix J. Ethanol-compatible oil for two-stroke........................................................ J1 Appendix K. Efforts in Obtaining an Engine ................................................................ K1 Appendix L. 2000 Mercury 5 hp four-stroke outboard .................................................. L1 Appendix M. Additional Pro/E Drawings .................................................................... M1 Appendix N. Rubber and Ethanol Compatibility........................................................... N1 Appendix O. EDS Results ............................................................................................ O1 Appendix P. Cold-start Options .....................................................................................P1 Appendix Q. Idle Speed Emissions Testing .................................................................. Q1 Appendix R. Tohatsu Power Curve............................................................................... R1 Appendix S. Mid-throttle Power Testing .......................................................................S1 Appendix T. Maximum RPM Values............................................................................ T1 Appendix U. Efficiency at Mid-Throttle ....................................................................... U1 Appendix V. Project Budgetary Assessment ................................................................. V1
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I. Introduction
The project is a novel study on the merits of using ethanol to power recreational
boats and of how ethanol could be integrated into said application.
Need Statement
Due to the potential for environmental contamination by gasoline in recreational
boating, fuel ethanol is a potential solution to reduce pollution associated with
recreational boating.
Objectives
The deliverables of the project are:
• Assess and quantify the environmental impact associated with gasoline
use in recreational boating
• Assess and quantify the potential environmental benefits associated with
ethanol use in recreational boating
• Determine recommended strategy for introducing fuel ethanol into
recreational boating market
• Determine and implement modifications necessary to convert a four-stroke
outboard engine to run on ethanol
• Assess ethanol’s performance relative to gasoline to determine market
viability
• Disseminate results and conclusion for interested parties
Given these deliverables, the project was broken into two parts: the first term
focused upon the theoretical implications of using fuel ethanol, while the second term
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focused upon the actual modification and testing of an outboard engine to support these
findings. For a complete timetable of the project, see Appendix B.
II. Problem Background
Major strides have been taken to curtail the pollution load from the transportation
sector, primarily because of the accumulation of adverse effects in urban areas. With the
introduction of additives in gasoline, internal combustion engines now burn cleaner,
improving air quality for many urban areas across the country. However, these
improvements have been realized primarily in highway vehicles, while other sectors such
as recreational boating continue to operate with less advanced technology. Because of
these factors, other applications besides highway vehicles now constitute a
disproportionately high amount of the overall air pollution load. For example, air
pollution studies in Minnesota place recreational watercraft as the third major contributor
to air toxins in the state in 1999.1
Besides air pollution, recreational boating poses another serious threat to the
environment in the form of water pollution. Currently, lakes and rivers are vulnerable to
point and non-point sources associated with recreational boating. A point source (PS) is
a source of pollution that can be positively traced to a single polluter. In the case of
recreational boating, the engine itself is a point source. Many emissions are inherent in
the combustion process, but may also include direct spillage into the lake by humans,
tanks, and fueling stations. A non-point source (NPS) is a source of pollution, which is
indirectly introduced as pollutants are carried by rain or snowmelt. In recreational
boating applications, non-point pollution may also occur as fueling stations and careless
1 Minnesota Pollution Control Agency, June 2003 <http://www.pca.state.mn.us/air/toxics/toxics-graphs.html>
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boaters spill fuel on land, which inevitably enters the lake or river during precipitation
events. In fact, the Environmental Protection Agency (EPA) recognizes this potential
environmental hazard and has offered programs and grants to control the contribution
from non-point sources.2
Like highway vehicles, the current fueling infrastructure for recreational boating
is gasoline-centered. Because of this, water pollution concerns associated with
recreational boating are mainly functions of gasoline as a contaminant in the
environment. Therefore, fuel choice is a major consideration in reducing environmental
contamination in recreational boating applications. The project’s goal is to examine the
prospect of an alternate fuel, ethanol, to reduce the adverse environmental impact of
recreational boating. See Appendix C for a brief discussion of other alternative fuels and
the current state of the art for all alternative fuels in marine engines.
Case Against Gasoline
In order to fully understand how contamination caused by gasoline will affect the
environment, the physical properties of gasoline and its numerous components must be
investigated. Because gasoline is a mixture of various compounds, the effects of gasoline
contamination vary by source – both the mixture of hydrocarbons and trace chemicals in
gasoline and the fuel additives. Automotive gasoline is typically unleaded and, according
to a material safety data sheet from MFA Oil Company, is comprised mainly of two
parts. These are the gasoline component (up to 95%) and the benzene (balance)3, but may
also contain approximately 10% of an oxygenating additive.
2 US EPA, Polluted Runoff (Non-Point Source Pollution), August 2003 <http://www.epa.gov/owow/nps/> 3 MFA Oil Material Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm>
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Once introduced into the environment, the components can act differently and
must be taken into account to reduce the effects of gasoline contamination. Because
gasoline is a highly volatile liquid, the lighter components of gasoline may evaporate into
fumes and vapor, even at ambient temperatures. Because gasoline fumes and vapor are
typically heavier than air, the hazard of exposure to humans is high near spills and
confined spaces.4 Specific hazards of gasoline vapor fumes can include neurotoxic
effects, and prolonged exposure has caused kidney problems and liver tumors in
laboratory rats. Hazards on humans are thought to be similar, though testing and
documentation do not exist. Although the vapors tend to photodegrade once in the air,
the potential hazard of the fumes to humans is relatively high, as most gasoline spills are
caused by humans and within close proximity to humans.
Once in contact with water, the lighter components may remain on the water
surface. As these components are generally lighter than water, the components will
remain at the water surface during calm weather. To accurately assess how gasoline will
behave once introduced in water, various factors must be taken into consideration,
including the amount spilled, the terrain of the lake, and the weather5. Human health
effects from skin contact can vary from skin irritation to kidney damage. From ingestion,
effects can vary from lung and liver damage and coma6. Gasoline is a known carcinogen.
Further information on toxicity for gasoline is found in Appendix D.
4 Material Safety Data Sheet-Chevron, Regular Unleaded Gasoline <http://library.cbest.chevron.com/lubes/chevmsdsv9.nsf/0/8002e031e024ef378825620c 000c2616?OpenDocument> 5 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000 6 MFA Oil Material Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm>
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Dose 5-10 ml to 18 ml 18+ ml 27-40 ml 26-76 ml 60-240 ml 115-
470ml Toxic Effects
Burning of GI tract,
abdominal pain
Burning of GI tract,
abdominal pain
As above Fever, convulsions,
unconsciousness
As above As above Normal fatal dose (much smaller if inhaled)
Table 1. Toxicity of Gasoline for an adult male. Onset of toxic effects from 10-48 hours of ingestion.
Source: O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000
Although gasoline is thought to biodegrade relatively quickly in the environment
(12-48 hours), this is highly dependent on whether the specific lake has biota able to
biodegrade the material. In fact, gasoline may persist in the environment for several
times longer if such biodegraders are not present. If biodegraders do exist, large spills
may render water anoxic, or deprived of oxygen, which can be detrimental to organisms
depending on the size of the spill. In addition, some components may degrade while
other non-degraded components persist in the water column.
A component in gasoline, benzene, is a contaminant that can be harmful in both
vapor and liquid phases. Benzene is a known carcinogen and has high potential to cause
kidney and liver damage. Because of this, benzene is highly monitored by the EPA for
drinking water quality7. Estimates on benzene biodegradation range from two days to
two weeks in water, and up to 17 days in air, depending on the season.
Recently, oxygen-containing chemicals were added to gasoline for cleaner
combustion, therefore decreasing air emissions. In the event of a spill, these additives
must also be considered as a potential health hazard. Currently, the fuel additive methyl
tertiary butyl ether (MTBE) is under much scrutiny due to its proposed effects on human
health. MTBE and its effects are important to consider due to its multi-faceted nature of
7 US EPA, Groundwater and Drinking Water, Technical fact sheet: benzene, Nov. 2002 <http://www.epa.gov/OGWDW/dwh/t-voc/benzene.html>
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exposure to humans. MTBE can be inhaled as a gas, ingested if it spreads to contaminate
groundwater, or even absorbed through the skin. Although the effects to human health
are still currently being tested8, MTBE contamination from gasoline has been highly
scrutinized; many states9, such as Colorado and California, have aggressively pursued
strict regulations of MTBE and the addition of ‘cleaner’ additives10. In fact, regulations
on drinking water have further reduced MTBE threshold amounts and have lead to a ban
of MTBE in California, and the discussion of a nationwide ban.
MTBE is a contaminant of interest because it readily dissolves into water, up to
30 times more than other petrochemicals in gasoline. Because of this, the MTBE in
gasoline can contaminate large volumes of water (one gallon of MTBE can contaminate
four million gallons of water11) and can remain and travel through water systems. Also
volatile, MTBE may find its way into the atmosphere, though MTBE photodegrades
quickly in the atmosphere with ultraviolet light. Unfortunately, its high solubility in
water prevents this method of degradation and allows it to enter the anthropogenic water
cycle, where potential for human exposure is drastically increased. These properties of
MTBE make gasoline spills a paramount concern, especially in lake areas.
When combusted in an engine, gasoline has many pollutant byproducts of
interest. Among the most important are carbon monoxide (CO), oxides of nitrogen
(NOx), carbon dioxide (CO2), and particulate matter with diameters of 2.5 micrometers
(PM2.5) and 10 micrometers (PM10). In an outboard engine air emissions are an important 8 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 2001) 375 9 Nancy E. Kinner, Testimony before the U.S. Senate Committee on Environment and Public Works, University of New Hampshire, April 23, 2001 10 US EIA, Status and Impact of MTBE bans, March 2003 <http://www.eia.doe.gov/oiaf/servicerpt/mtbeban/table1.html> 11 Nancy E. Kinner, Testimony before the U.S. Senate Committee on Environment and Public Works, University of New Hampshire, April 23, 2001
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consideration, not only for their impact on air quality, but also because the absence of a
muffler causes air emissions to be injected into the water. Therefore, reductions in air
emissions may significantly reduce the impact on water quality as well.
Carbon monoxide is a colorless and odorless poisonous gas, which is produced
when gasoline is burned in less optimal conditions. The resultant carbon monoxide gas
poses a major health hazard to humans. As an asphyxiant, carbon monoxide gas retards
the body’s ability to transport oxygen to parts of the body12. Because of this, even small
quantities of carbon monoxide in the air can have much larger secondary effects, due to
hemoglobin’s high affinity for CO (up to 210-250 times that of oxygen13). Carbon
monoxide poisoning and death during recreational boating activity is not uncommon; the
National Institute for Occupational Health and Safety is aware of 106 CO poisonings
specific to recreational boating14
Another set of pollutants, the oxides of nitrogen, are of concern to gasoline
combustion in recreational boating. These compounds are the result of nitrogen
oxidation, namely when nitrogen is oxidized in the combustion air under high
temperatures or oxidized in gasoline itself. Nitric oxide (NO), which often constitutes the
majority of nitrogen oxide pollutants, can react with oxygen in air to produce nitrogen
dioxide (NO2), a known human health hazard. When inhaled, the gas can often cause
lung irritation as well as bronchitis and pneumonia.
12 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 1998) 343-344. 13 US Dept. of Health and Human Services. “Carbon Monoxide Emissions and Exposures on Recreational Boats Under Various Operating Conditions” Feb. 2003 <safetynet.smis.doi.gov/Report%20171-05ee2.pdf> 14 US Dept. of Health and Human Services. “Carbon Monoxide Emissions and Exposures on Recreational Boats Under Various Operating Conditions” Feb. 2003 <safetynet.smis.doi.gov/Report%20171-05ee2.pdf>
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NOX emissions also have lasting secondary effects. Once in the atmosphere, it
can react with OH, a hydroxyl radical, to form nitric acid, which is a contributor to the
problem of acid rain. Its effects can also be seen in the reddish-brown smog over
urbanized areas, such as Los Angeles. When able to react with other pollutants, such as
evaporated hydrocarbons and other volatile organic compounds (VOCs) and with
sunlight, oxides of nitrogen can form secondary pollutants called photochemical oxidants.
Among these are ozone (O3), which is damaging to human health and vegetation, and eye
irritants such as formaldehyde (HCHO)15. Ozone levels can become a problem in
localized areas, such as Lake Tahoe, where ozone levels are affecting surrounding plants
and organisms16. Like carbon monoxide, nitric oxide and nitrogen dioxide have been
major targets of reductions in air quality policy due to the direct and secondary adverse
health effects.
Carbon dioxide is an important element in emissions because of its contribution to
the greenhouse effect. Though the notion that rising carbon dioxide in the atmosphere is
causing global warming is still under question17, carbon dioxide and greenhouse gases
have been major targets in recent international environmental policy, as seen in the Kyoto
Protocol18. Although not as immediate of a consideration when considering impacts on
human health and the environment from boating, the overarching effects of carbon
dioxide as an emission are still viable concerns when considering emissions from a more
general stand point. 15 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 1998) 344-345 16 US Water News Online, “Experts study effects of Sacramento pollution on Lake Tahoe” Sept 2003. <http://www.uswaternews.com/archives/arcquality/3expstu9.html> 17 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 1998) 477 18 Government of Canada, Canada and the Kyoto Protocol, July 2001, viewed 10/17/03 <http://www.climatechange.gc.ca/english/whats_new/overview_e.html>
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Particulate matter is a general health concern because it can cause respiratory
illness. The EPA currently regulates the load in air19, and trends have shown steady
decreases over the last decade. PM2.5 and PM10 can be a result of the combustion process,
but may also be formed from secondary reactions from NOX and SO2.
In response to these considerations, the altering of ordinary gasoline fuels has
been suggested as one method to reduce such pollution. The process of oxygenating
gasoline allows for a ‘cleaner’ burning process, which results in cleaner emissions. One
fuel of interest is ethanol20. Recently, ethanol has become an additive in gasoline to
reduce the negative effects on seasonal air quality.
One last consideration in fuel choice is renewability and sustainability. Gasoline
is a petroleum-derived product, and as with any fossil fuel derivative, the lifetime of
gasoline is limited.
III. Case for Ethanol
The objective of the project was to examine ethanol’s use as fuel in recreational
boating. Although other energy sources have been implemented into boating
applications, ethanol provides unique benefits to recreational boating. A discussion of
the alternatives can be found in Appendix C.
Ethanol is a simple grain alcohol, commonly found in alcoholic beverages. With
its long history of human consumption, the hazards of ethanol to human health and the
environment are well understood and perceived to be much less than with gasoline. In
19 US EPA, Air trends summary: PM-10. April 2002. <http://www.epa.gov/air/aqtrnd95/pm10.html> 20 William W. Nazaroff and Lisa Alvarez-Cohen, Environmental Engineering Science, (New York: John Wiley & Sons, Inc, 2001) 282
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fact its toxicity is much less than that of gasoline for humans21 (additional toxicity data
for ethanol are found in Appendix D). Further, a report by the Governors’ Ethanol
Coalition concluded that ethanol poses no threat to ground or surface water, and is
expected to biodegrade rapidly in all environments22. On a fundamental level, ethanol is
comprised of far fewer components than the hundreds of chemicals, some carcinogenic,
of which gasoline is comprised23. This implies a simpler fate and transport process and
remediation for ethanol than for gasoline.
Unlike gasoline, which depends heavily on a specific type of organism for
biodegradation, ethanol is naturally occurring and is readily biodegradable. Estimates for
biodegradation half-life range from 0.5-5.0 days in vapor form and 0.1-2.1 days in
surface water24. This can vary significantly depending on season and terrain, as with
gasoline, but the ranges of biodegradation times are lower for ethanol, implying more
biodegradability than gasoline in similar conditions.
Although solubility in water can pose a potential threat in the case of toxic
chemicals, ethanol is relatively non-toxic, and its infinite solubility in water allows for
ethanol to be readily diluted to non-toxic levels25. Along with biodegradation comes the
potential for anoxia in water. However, because of the stratified aspect of lakes, spills
can often be contained at the surface where decreased oxygen levels will be localized,
21 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 22 Governors’ Ethanol Coalition, “Fate and Transport of Ethanol-Blended Gasoline in the Environment” Oct. 1999 23 Conversation with Professor Benoit Cushman-Roisin Dec. 12, 2003 24 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 25 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000.
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minimizing effects to the lake as a whole. In the case of spills in more turbulent water
(e.g. a river), this is not as large of a concern, as oxygen-rich water is always in supply.
The vast disparity in toxicity levels between ethanol and petroleum-based fuel is
illustrated in the March 1, 2004 tanker explosion off the coast of Virginia. The tanker
was carrying 3.5 million gallons of industrial ethanol; however, according to a U.S. Coast
Guard spokesman, “the 700 tons of fuel oil carried by the tanker [were] a greater cause
for concern than the ethanol.”26
The change in human health effects is said to be minimal with the addition of
ethanol, as the oxygenate is relatively non-toxic in comparison to gasoline27. However,
recent research indicates that when ethanol is blended with gasoline, ethanol may be
‘preferentially’ biodegraded over compounds found in gasoline. This is most likely due
to the absence of biodegrading organisms. In such an instance, ethanol would readily
biodegrade, while compounds, such as BTEX (benzene, toluene, ethylbenzene, and
xylene), are allowed to continue fate and transport processes. Furthermore, ethanol in
gasoline may, in fact, increase BTEX plumes in groundwater28. Though research is
currently trying to justify these claims, ethanol-gasoline blends may not be a proper
alternative to eliminating the potential harms from using gasoline, because of these
deleterious effects resultant from this type of fuel blending.
According to Dr. Charles Wyman, former director of the Center for Renewable
Fuels and Biotechnology at NREL, “ethanol is low in toxicity, volatility, and
26 Tanker Carrying Ethanol Explodes and Sinks off of U.S. Coast, 2004, United Nations Foundation, 5 March 2004, <http://www.unwire.org/UNWire/20040301/449_13567.asp>. 27 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 28 Powers, Susan, et al. “Transport and fate of ethanol and BTEX in groundwater contamination by gasohol” 2000.
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photochemical reactivity, resulting in reduced ozone formation and smog compared to
conventional fuels.” 29 Although the potential for a reduction in air emissions is apparent,
little data exist for recreational boating. However, the addition of ethanol as a blending
fuel in gasoline and the benefits on air emissions are documented for automobiles. In one
study, with the introduction of ethanol up to 10% (E10), significant reductions were
realized in particulate matter and carbon monoxide emissions30. Further, reductions were
seen in CO2 emissions as well as overall fuel consumption in some of the vehicles tested.
No significant change was found for NOX emissions. In another study with a blended
gasoline with up to 85% ethanol (E85), reductions were seen in NOX and CO2 emissions,
with increases in CO and hydrocarbons. In general, lower proportions of ethanol tend to
decrease criteria pollutants in the combustion process. But, as the proportion of ethanol
becomes higher, emissions can increase due to inefficient burning because engines are
designed to run on gasoline and are not tuned for ethanol. In the case of recreational
boats, a similar trend is expected, as engines are built to run primarily on gasoline, until
the technology seen in automobiles can be adapted to recreational boating applications.
Although variant on actual engine design, the EPA expects a 15% reduction in
ozone-forming VOCs, a 40% decrease in CO emissions, a 20% decrease in PM, and a
10% decrease in NOX31 for E85 fuel, and presumably more for E95 or pure ethanol.
Critics of ethanol as a fuel often point to emissions increases to deter ethanol usage; the
use of ethanol in a combustion engine may also increase the acetaldehyde emissions32.
29 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 30 AEA Technology. “Ethanol Emissions Testing” March 2002. 31 US EPA ethanol fact sheet, Mar 2002 <http://www.epa.gov/otaq/consumer/fuels/altfuels/altfuels.htm#fact>. 32 M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994).
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However, a study by the California Environmental Policy Committee found that although
acetaldehyde emissions were greater in ethanol fueled engines, emissions of more toxic
compounds such as formaldehyde were also reduced, offsetting the slight increase found
in acetaldehyde33.
In terms of the future of the fuel, ethanol is renewable and is more sustainable
than gasoline. The potential for sustainability is high as research is currently underway to
make ethanol from various forms of plant biomass. Thus, the implementation of ethanol
in recreational boating may not only increase the environmental performance of outboard
engines from a water and air pollution standpoint, but also decrease the overall demand
for gasoline. This implementation may catalyze the introduction of other alternative
energies to further increase energy sustainability as a whole.
Current Feedstocks Fuel Energy: Fossil Energy Future Potential Usually corn in US, but any
sugar crop can be used. 1.25:1 (all production
energy assumed to be fossil based
Non-corn bioethanol may offer higher energy
efficiency. Woody biomass may also be a future stock.
Table 2.Feedstocks, fuel energy to fossil energy ratio and future potential of the renewability of ethanol.
Fuel energy: Fossil energy gives the ratio of energy contained in the fuel as compared to the fossil fuel energy required to create/support the given fuel through its life cycle. Adapted from: O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. Aquatic Toxicity Analysis
According to Benoit Cushman-Roisin, professor in environmental engineering at
Dartmouth College, ethanol is less detrimental to aquatic environments than gasoline34.
To verify this, a simple analysis is presented in order to compare the environmental
33 Renewable Fuels Association, “Ethanol and the Environment” <http://www.ethanolrfa.org/factfic_envir.html> 34 Conversation with Prof. Benoit Cushman-Roisin. Dec. 12, 2003
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performance of each fuel in water. A hypothetical scenario of a spill of 50 kg will be
assessed for both gasoline and ethanol. Assuming some lake surface area of 1 km2, and
an effective mixing depth of 10 m (due to a seasonal thermocline), it can be assumed that
the effective mixing volume will be a product of one half the length and width of the lake
surface (area = 250,000 m2) and the depth, or 2,500,000 m3. If 50 kg of gasoline is
spilled and mixed into the given water volume, the gasoline concentration in the water
will be 20 micrograms per liter, the aquatic toxicity threshold for gasoline in water35. In a
similar situation, 50 kg of ethanol spilled and mixed, the aquatic toxicity does not exceed
the threshold of 14,760 micrograms per liter36. It is clear that an equivalent spill of
ethanol would have far less ecological effects on the aquatic life than in the event of a
gasoline spill. This scenario is a generalization, but gives insight on the impacts of each
fuel on the environment.
IV. Specific Focus: California
The United States does not have uniform fuel prices and environment regulations;
therefore, a specific area needs to be chosen as a case study to better understand the
feasibility of introducing fuel ethanol into recreational boating.
Case for California
California was chosen as the state to focus the study for a number of reasons.
California has the second highest number of boats in the United States, so there is a large
target market. Additionally, one of the primary concerns of ethanol's use as a fuel was its
price, which is typically higher than gasoline. California, with one of the highest
35 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 36 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000.
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gasoline prices in the country, could provide a market where ethanol prices could be
competitive with gasoline. However, the most important reason for targeting California
has to do with their tough environmental regulations and support of alternative fuels.
California has the toughest emissions regulations in the country; in fact all outboard
engines are rated not just on EPA regulations, but also California Air Resource Board
regulations. Additionally, California has more alternative fuel stations than any other
state in the U.S.37 Most alternative fuel technologies get their start in California; when
major automakers produce alternative fueled or electric vehicles, the first test market is
almost always in California. In conclusion, California represents the most supportive
environment for introducing ethanol-powered boat engines, and would hopefully allow
the technology to become established before expanding nationwide.
Environmental Regulations
The United States began to work to lower water and air pollution through the
Environmental Protection Agency (EPA) with the 1970 Clean Air Act38 and 1977 Clean
Water Act39. Through the intermittent years the regulations have become more stringent
and specific. Now, there are established federal air pollution control standards for
recreational boats using gasoline-powered outboard engines.
The Federal Water Pollution Control Act prohibits the discharge of oil or
hazardous substances into US waterways. This includes “any discharge that produces a
film or discoloration of the surface of the water or causes a sludge or emulsion beneath
37 Alternative Fuels Data Center, Alternative Fuel Station Counts Listed by State and Fuel Type (Dept. of Energy 1 Dec. 2003, <http://www.afdc.doe.gov/refuel/state_tot.shtml>. 38 The Plain English Guide to the Clean Air Act, 1993, EPA – Air Quality and Standards, 28 Nov. 2003, <http://www.epa.gov/oar/oaqps/peg_caa/pegcaain.html>. 39 The Clean Water Act, 2003, EPA – Laws and Regulations, 28 Nov. 2003, <http://www.epa.gov/region5/water/cwa.htm>.
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the surface of the water.”40 The current exhaust emissions standards are applicable to
new marine spark-ignition outboard and personal watercraft engines beginning with the
1998 model year. The EPA only regulates hydrocarbon and nitrogen oxide emissions.
Hydrocarbon Plus Oxides of Nitrogen Exhaust Emission Standards [grams per kilowatt-hour]
Model year P < 4.3 kW HC+NOX P ≥ 4.3 kW HC+NOX
1998 278.00 (0.917 x (151 + 557/ (P0.9)) + 2.44
1999 253.00 (0.833 x (151 + 557/ (P0.9)) + 2.89
2000 228.00 (0.750 x (151 + 557/ (P0.9)) + 3.33
2001 204.00 (0.667 x (151 + 557/ (P0.9)) + 3.78
2002 179.00 (0.583 x (151 + 557/ (P0.9)) + 4.22
2003 155.00 (0.500 x (151 + 557/ (P0.9)) + 4.67
2004 130.00 (0.417 x (151 + 557/ (P0.9)) + 5.11
2005 105.00 (0.333 x (151 + 557/ (P0.9)) + 5.56
2006 and later 81.00 (0.250 x (151 + 557/ (P0.9)) + 6.00
Where P = the average power of an engine in the model year in kW Table 3. EPA Exhaust Emission Standards41
The emissions standard that corresponds to the 2006 and later model years is commonly
referred to as the “EPA 2006 Standards.” The federal regulations are intended to reduce
HC + NOx emissions from outboard and personal watercraft engines by 75 percent by
2025.42
40 Pollution Regulations, 2003, US Coast Guard, 30 Nov. 2003, <http://www.uscgboating.org/safety/fed_reqs/equ_pollution.htm>. 41 Control of Air Emissions from Marine Spark-Ignition Engines, 2003, EPA – Air Programs, 31 Oct. 2003, <http://ecfrback.access.gpo.gov/otcgi/cfr/otfilter.cgi?DB=3&query=40000000091®ion=BIBSRT&action=view&SUBSET=SUBSET&FROM=1&SIZE=10&ITEM=1#Sec.%2091.101>. 42 Emission Standards and Test Procedures for New 2001 and Later Model Year Spark-Ignition Engines, 1999, Air Resources Board, 25 October 2003, <http://www.arb.ca.gov/regact/marine/fsor.pdf>.
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Because the federal program is not sufficient to meet California’s State
Implementation Plan (SIP) requirements or air quality goals, a more progressive program
was necessary. California’s exhaust emission allotments are much lower – as the EPA
2006 Standards are at the lowest tier. The emission standards – as determined by the
California Air Resources Board (CARB) – are applicable to new 2001 and later year
models of spark-ignition marine engines.
Hydrocarbon Plus Oxides of Nitrogen Exhaust Emission Standards
[grams per kilowatt-hour] Model year P < 4.3 kW HC+NOX P ≥ 4.3 kW HC+NOX
2001 81.00 (0.250 x (151 + 557/ (P0.9)) + 6.00
2004 64.80 (0.20 x (151 + 557/ (P0.9)) + 4.80
2008 30.00 (0.09 x (151 + 557/ (P0.9)) + 2.10
Where P = the average power of an engine in the model year in kW Table 4. CARB Exhaust Emission Standards43
In addition, no new spark-ignition marine engines may be produced for sale to replace
spark-ignition marine engines in pre-2001 model year equipment after the 2004 model
year, unless those engines comply with the 2001 model year emission standards.44 For a
graphical representation of the emission standards, see Appendix E. To facilitate sale of
outboard engines in California, CARB has implemented engine labels45 based upon the
emission standards:
One Star - Low-Emission • meets the Air Resources Board’s 2001 exhaust emission standards • 75% lower emissions than conventional carbureted two-stroke engines • equivalent to the U.S. EPA’s 2006 standards
43 Air Resources Board, California Exhaust Emissions Standards and Test Procedures for 2001 Model Year and Later Spark-Ignition Marine Engines (1999) 4. 44 Air Resources Board, California Exhaust Emissions Standards and Test Procedures for 2001 Model Year and Later Spark-Ignition Marine Engines (1999) 5. 45 California Code of Regulations, Chapter 9 Off-Road Vehicles and Engines Pollution Control Devices, section 2443.3 3.
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Two Stars - Very Low Emission • meets the Air Resources Board’s 2004 exhaust emission standards • 20% lower emissions than One Star - Low-Emission engines
Three Stars - Ultra Low Emission • meets the Air Resources Board’s 2008 exhaust emission standards • 65% lower emissions than On Star - Low Emission engines
The CARB regulations will dually result in a reduction of water pollution.46 In
addition to very strict exhaust emission standards, California has implemented strategies
to lessen the water pollution issues caused by gasoline-powered engines. MTBE – an
additive – has been banned and was phased out by December 31, 2003. Some large lakes
such as Lake Tahoe, Echo Lake, Cascade Lake, and Fallen Leaf Lake47 have taken a
more direct route by prohibiting the use of carbureted two-stroke boat engines,
implemented by Tahoe Regional Planning Agency48. Only two-stroke direct injection
and four-stroke engines are permitted on the lakes. These regulations hope to further
protect the environment from the harmful effects of the outboard engine emissions.
Infrastructure for introducing ethanol as a fuel in California
As stated earlier, MTBE has been banned as a fuel oxygenate in California. The
phase-out of MTBE and substitution of ethanol (the only approved substitute by the
California Environmental Policy Council) was complete by the end of 2003 and makes
California the United States’ largest market for ethanol fuel.49 This infrastructure would
only need to be appended in order to supply marinas with ethanol as a fuel for boats.
46 New Regulations for gasoline marine engines, 1999, Air Resources Board, 12 Nov. 2003, <http://www.arb.ca.gov/msprog/marine/facts.pdf>. 47 A Consumer’s Guide to Lake Tahoe, Tahoe Regional Planning Agency, 12 Nov. 2003, <http://www.dbw.ca.gov/Pubs/Blt/>. 48 A Consumer’s Guide to Lake Tahoe, Tahoe Regional Planning Agency, 12 Nov. 2003, <http://www.dbw.ca.gov/Pubs/Blt/>. 49 California Energy Commission, Ethanol Supply Outlook for California (2003) 1.
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The infrastructure takes into account ethanol production and supply, ethanol
transportation to California markets, and ethanol storage and distribution within
California – resulting in a retail price for ethanol.
In 2004, California is expected to require between 760 and 990 million gallons of
ethanol for gasoline blending. In the next few years, the majority of the ethanol needs
would be satisfied by domestic ethanol producers with no more than 10% coming from
foreign sources such as Brazil. Most of the domestic ethanol is made from corn in the
Midwest. Between 2001 and 2003, the United States’ ethanol production grew by 38% -
an increase of 870 million gallons per year – from 2.22 to 3.07 billion gallons of ethanol.
The number of operating ethanol plants increased from 57 to 69. There are 16 new
facilities under construction that would 767 million gallons to the total capacity by the
end of 2006. In addition, 50 projects are planned that would increase the capacity by 2
billion gallons at the close of 2006.50 There have also been discussions of expanding
California’s ethanol production through conventional corn-to-ethanol projects, sugarcane-
to-ethanol projects, and waste biomass-to-ethanol projects.51 For an explanation of the
various methods of producing ethanol, see Appendix F. The supply of ethanol will be
able to handle the increased demand introduced by the California ban of MTBE.
50 California Energy Commission, Ethanol Supply Outlook for California (2003) 2. 51 California Energy Commission, Ethanol Supply Outlook for California (2003) 11.
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Figure 1. USA Ethanol Production Capacity52
The next step is to transport and distribute the fuel ethanol. Because of the large
distance between the Midwest and California, only two transportation methods are viable
– rail shipments and marine cargoes, although pipelines53 are being considered. Rail
shipments normally consist of one of more 30,000-gallon rail cars, filled about 97%.
Two to three weeks would be needed for transit from the Midwest to California –
resulting in about four to six weeks for one complete turnaround. Marine cargoes of
multiple 10,000-barrel river barges would travel down the Mississippi River through the
Panama Canal to the California Pacific Coast – taking a minimum of 34 days. Shipments
could range from 1 to 12 million gallons, although 4-5 million gallons would be more
typical. It is important to note that 1.2 to 1.7 million gallons of MTBE per day is shipped
52 California Energy Commission, Ethanol Supply Outlook for California (2003) 7. 53 Ethanol and Market Opportunities, 2000, RFA, 1 Nov. 2003, <http://www.ethanolrfa.org/factfic_market.html
Ethanol as Fuel for Recreational Boats Final Report
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from the gulf coast to the west coast, and this capacity could be redirected for ethanol
transportation. There is no significant economic advantage for using one of the methods
over the other, so the location of the ethanol plant would be the deciding factor.54 Once
the ethanol arrives in California, it would be redistributed via truck or rail to centrally-
located final destination terminals, where it would be blended with gasoline before being
redistributed to gas stations for sale.
The retail price of ethanol must include the production and transportation costs as
well as any relevant taxes. Its production costs are governed by the price of corn, which
has an effect on production volume, as the product must be priced to compete based upon
its value to the end user. The cost of shipping ethanol to California would cost between
14 and 17 cents per gallon and the handling charges at the central terminals would be in
the range of $0.006 to $0.017 per gallon. The minimum premium required to draw
ethanol from the Midwest octane market to California is five cents per gallon.55 The
current production cost of ethanol in Nebraska is $1.02 per gallon of ethanol.56 For a
look at the historical cost of fuel ethanol, see Appendix G. In addition, there is taxation.
Although California does not provide a formal tax exemption for ethanol, it does have an
excise tax rate of only $0.09 per gallon for 85% blends and above, as opposed to the
$0.18 per gallon tax on gasoline.57 The final component is the mark-up at the pump,
54 Downstream Alternatives, Inc., The Renewable Fuels Association, The Use of Ethanol in California Clean Burning Gasoline – Ethanol Supply/Demand (1999) 11-12. 55 Downstream Alternatives, Inc., The Renewable Fuels Association, The Use of Ethanol in California Clean Burning Gasoline – Ethanol Supply/Demand (1999) 31. 56 Mark Yancy, The Investment Climate for Ethanol Production in California, 2003, BBI, 29 Nov. 2003, <http://www.bbiethanol.com/doe/ca/Yancey-CA-DOE.pdf>. 57 Tax Rate on Ethanol or Methanol, 2003, Database of State Incentives for Renewable Energy, 29 Nov. 2003, <http://www.dsireusa.org/library/includes/incentive2.cfm?Incentive_Code=CA24F&state=CA&CurrentPageID=1>.
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which is typically 10 to 22 cents for gasoline, and will be assumed to be the same for
ethanol sales in California.58
Price Range for California Ethanol
(per gallon of ethanol) Production Cost $1.020 ─ $1.020 Price Incentive $0.050 ─ $0.050 Transportation/handling costs $0.146 ─ $0.187 Excise Tax Rate $0.090 ─ $0.090 Mark-up $0.100 ─ $0.220 Projected California Price Range $1.406 ─ $1.567 Gasoline Equivalent Price Range $1.223 ─ $2.366 Table 5. Projected Price Range for Ethanol Sale in California
The price is not expected to exceed $2.366 per gallon, which although high is still
comparable to the statewide average for regular gasoline at $1.691 as of 24 November
2003.59
A similar approach will need to be taken to evaluate the potential consumption
and price of ethanol in recreational boating applications on lakes. According to the US
Coast Guard, California had the second most boats in use in 2000 with 904,863 registered
boats behind only Michigan.60 Of those boats, 350,039 of them used outboard engines.61
According to the California Department of Boating and Waterways62, the
Recreational Boat Building Industry63, the Recreational Boating and Fishing
Foundation64, the Energy Information Administration65, and the U.S. Department of
58 John Cruger-Hansen, “Re: fuel docks,” email to the author, 15 Nov. 2003. 59 Transportation Fuels: Gasoline, Diesel, Ethanol, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/index.html>. 60 US Department of Transportation, United States Coast Guard, Boating Statistics – 2000 (2000) 24. 61 US Department of Transportation, United States Coast Guard, Boating Statistics – 2000 (2000) 25. 62 Department of Boating and Waterways, 2003, California, 4 Nov. 2003, <http://www.dbw.ca.gov/index.htm>. 63 Power Boat Industry Statistics, Recreational Boat Building Industry, 7 Nov. 2003, <http://www.rbbi.com/desks/mkt/stats/stats.htm>. 64 Stephanie Hussey, “Ethanol as a fuel for recreational boating,” email to the author, 19 Nov. 2003. 65 Curley Andrews, “RE: gasoline consumption in boats,” email to the author, 17 Nov. 2003.
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Transportation – Bureau of Transportation Statistics66, no surveys have been taken on the
national or California level that differentiate between the number of two-stroke and four-
stroke outboard engines currently used recreationally. A survey was conducted by the
Wisconsin Department of Natural Resources and the University of Wisconsin Survey
Center for boats registered in Wisconsin in order to determine a gasoline consumption
estimate for recreational boating in 2000. The survey found that the average estimate of
gasoline consumption for Wisconsin boaters was 58.69 gallons in 200067 and that 20% of
the boaters had four-strokes, 12% did not know, and the remainder had two-strokes.68
For the purpose of this study, it will be assumed that the information is the same for
California; therefore, there were 70,008 four-stroke outboard engines in use in California
in 2000.
The 70,008 four-stroke engines consumed 4,108,770 gallons [70,008 x 58.69] of
gasoline in 2000 at a rate of 1.58 gallons per hour.69 There are generally two ways to
relate a volume of gasoline to a volume of ethanol – the energy content of the fuel and
having an engine optimized for the specific fuel. The energy content of gasoline is
115,000 Btu/gal, where as ethanol has an energy content of 76,100 Btu/gal.70 This results
in 1.51 gallons of ethanol being equivalent to one gallon of gasoline. On the other hand,
if the engine were optimized to run on ethanol, there would be a 15% efficiency
improvement over gasoline71 – corresponding to 0.87 gallons of ethanol being equivalent
66 Answers, “RE: gasoline consumption in boats,” email to the author, 17 Nov. 2003. 67 Eugene Lange, “Gasoline Consumption Estimate for the 2000 Recreational Boating Survey,” State of Wisconsin – Department of Natural Resources. 2002. 68 Edward Nelson, “RE: gasoline consumption in boats,” email to the author, 20 Nov. 2003. 69 Tahoe Regional Planning Agency, Environmental Assessment for the Prohibition of Certain Two-Stroke Powered Watercraft (1999) 10. 70 Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished. 5-6. 71 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000, 105.
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to one gallon of gasoline. If all of the four-stroke outboard engines replaced gasoline
with ethanol, 3.57 million [optimized engine] to 6.20 million gallons [energy content] of
ethanol would be required. Mentioned earlier, the United States expects to have the
capacity to produce approximately 4 billion gallons of fuel ethanol in 2004. Adding the
ethanol needed to replace MTBE to the values just calculated would result in California
requiring approximately 764 million to 996 million gallons of ethanol in 2004. This is
not a significant increase from the supply needed to replace MTBE; therefore, there will
be an adequate supply of ethanol to meet all of California’s needs. See Appendix H for
the aforementioned calculations.
Ethanol is already being transported to California and distributed within the state.
The only additional cost considerations are those that deal directly with selling fuel on a
lake. Marine fuel docks have significantly higher operating costs than land-based gas
stations. Waterfront property commands a much higher price than regular roadside
property that houses regular gas stations, resulting in higher mortgage payments. The
environmental regulations are stricter because anything spilled immediately enters the
water. Accordingly, there must be a large amount of spill cleanup gear and the
employees must have training equivalent to HAZWOPPER (OSHA’s hazardous waste
operations and emergency response protocol) in order to use the spill gear. Finally,
marina fuel docks have limited operating seasons and hours so the sales volume is
generally less than a regular gas station. The 35 cents per gallon attempts to compensate
for the higher operating costs.72 It is assumed that similar operating costs would be
required for ethanol to be dispensed at marinas. The spill preparation would most-likely
be relaxed, but added costs would be required to convert the fuel pump to carry ethanol. 72 John Cruger-Hansen, “Re: fuel docks,” email to the author, 15 Nov. 2003.
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Price Range for California Ethanol Sold at Marinas
(per gallon of ethanol) Production Cost $1.020 ─ $1.020 Price Incentive $0.050 ─ $0.050 Transportation/handling costs $0.146 ─ $0.187 Excise Tax Rate $0.090 ─ $0.090 Mark-up $0.350 ─ $0.350 Projected California Price Range $1.656 ─ $1.697 Gasoline Equivalent Price Range $1.441 ─ $2.562
Table 6. Projected Price Range for Ethanol Sale in California at Marinas
The price is not expected to exceed $2.562 per gallon of gasoline, which is still
comparable to the statewide average for regular gasoline at $1.991 – adjusted for
lakeshore consumption from 6/16/03 to 9/15/03.73 See Appendix H for the adjustment
calculation.
A major obstacle for introducing fuel ethanol into marine applications involves
the necessary modifications to the existing fueling facilities. With blends of 85% ethanol
and greater, many parts would need to be replaced.
The pumps, hoses, nozzles, safety breaks, swivels, and all internal metal parts touching the fuel must be made of certain materials that withstand this toxic blend of chemicals. In this case, the recommended materials for the metal are 'stainless steel' or 'nickel-plated steel' (both items make the cost of the equipment more than double and often go up by 250% to 500%). Even with these two materials, manufacturers most often will not warranty any equipment more than 30 to 90 days if used with ethanol blends.74
Gasboy, a division of Gilbarco, is the only manufacturer of pumps for 85% and higher
ethanol blended fuel; Gilbarco has discontinued this line of products while researching
them further. Tuthill (Fill-Rite) and Great Plains Industries are investigating
manufacturing pumps for this application. Tuthill (Fill-Rite) does have pumps
73 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>. 74 Donlee Pumps, “Re: ethanol storage in marinas in CA,” email to the author, 2 Dec. 2003.
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commercially available for lower blends and is working on extended models, such as a
marina.75
California’s high gasoline prices make ethanol economically competitive,
suggesting that California is a feasible location to introduce it into recreational boating
applications. The study above focused upon the conventional technology where ethanol
is produced from corn. Newer technologies that convert waste biomass to ethanol, when
fully established, would provide a cheaper source of ethanol. Currently, cellulosic
ethanol is produced at similar prices to corn ethanol ($1.10 to $1.20/gal).76 Fuel ethanol
would already be cheaper if the engine was optimized for it. The federal government
currently offers a one-time income tax reduction of up to $2,000 with the purchase of a
clean-fuel vehicle (which includes fuels with at least 85% ethanol).77 Although the tax
incentive only applies to motor vehicles, one can assume that if a viable alternative to
gasoline-powered outboard engines was available, a similar tax deduction could apply.
Provided support from the government, ethanol could replace gasoline in four-stroke
outboard engines on an economic basis.
Up until this point the considerations for ethanol’s use as a fuel have been
discussed; however, in the following sections the methodology for its use in an outboard
engine can be explored.
V. History of Ethanol Use in Engines
Ethanol’s use as an alternative fuel dates back to the original Otto engine
developed in 1877, and the Ford Model T of 1908. The Model T was originally designed
75 Donlee Pumps, “Re: ethanol storage in marinas in CA,” email to the author, 2 Dec. 2003. 76 Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished. 28. 77 Tax Incentives for Electric and Clean-Fuel Vehicles, 2003, Fueleconomy.gov, 9 Nov. 2003, <http://www.fueleconomy.gov/feg/tax_afv.shtml>.
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to run on ethanol, however as oil companies began to push the dominance of gasoline for
internal combustion, the Model T was converted to run on gas and ethanol as a fuel was
largely forgotten. It was until the 1970’s, and the oil crisis which drove gas prices to
historical highs, that ethanol reemerged as a viable alternative to gasoline. In the late
1970’s, 10% blends of ethanol and gasoline, commonly known as gasohol, became
widely available as an alternative to pure gasoline. At the same time, Brazil began a
program to introduce ethanol blends and 100% ethanol as an automotive fuel. It wasn’t
until the 1990’s, however, that the potential for vehicles primarily fueled on ethanol
began to be explored.
Brazil has set the example for the US to follow, as automobiles in Brazil have
been fueled on ethanol since the 1970’s. Currently, all cars in Brazil run on at least 22%
ethanol (with the remaining 78% being gasoline), including an estimated 40% which run
on 100% ethanol78. Brazil produces between 3 and 4 billion gallons of ethanol per year, a
large amount of which is exported to other countries, including the US. At its height in
the early 1980’s, as much as 75% of all vehicles produced ran on pure ethanol. While
that number has since plummeted to around 1% as the oil price shock subsided, the new
standard has been vehicles fueled on a 20-25% ethanol blend79.
In the United States, ethanol has been gaining popularity in the Midwest as a
viable alternative for 100% gasoline. Currently, there are 179 refueling stations in the US
that offer E85, an 85% blend of ethanol with gasoline80. The majority of these refueling
stations are based in the Midwest, as the center of US ethanol production is located in the 78 Introduction to Ethanol, Northwest Iowa Community College, 17 Oct. 2003, <http://www.nwicc.com/Module1.htm>. 79 São Paulo Sugarcane Agroindustry Union, 17 Oct. 2003, <http://www.unica.com.br/i_pages/estatisticas.asp#>. 80 Alternative Fuel Station Counts, 17 Oct. 2003, Alternative Fuel Data Center, 17 Oct. 2003, <http://www.afdc.nrel.gov/refuel/state_tot.shtml>.
Ethanol as Fuel for Recreational Boats Final Report
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Corn Belt. US automakers have responded enthusiastically to the increased demand for
vehicles capable of running on E85; Ford and GM have both increased production of
FFV (flex-fueled vehicles), capable of running on both E85 and pure gasoline. There are
approximately 3 million vehicles on the road equipped to run on E85, and GM has plans
to expand production of FFV to more models81. Additionally, all vehicles in the US can
run on E10, commonly known as gasohol, which contains 10% ethanol82.
Each year, the number of ethanol-powered vehicles in the US has been growing,
from a mere 441 vehicles in 1993 to over 82,000 in 2002 (this value does not include the
almost 3 million FFV, which can run on ethanol, but are primarily run on gasoline). A
staggering 78% of these vehicles are in operation in the Midwest, while ethanol has yet to
infiltrate the northeast, with a 2% share83. Still, the demand for ethanol is increasing as
well; the US currently consumes over 10 million gallons of E85, up from just 48,000 in
199384.
Until recently, marine applications for ethanol have been largely ignored,
however as the popularity of ethanol fueled automobiles spreads, it has begun to spread
to boats as well. Currently, all of the major outboard engine manufacturers approve 10%
ethanol blends for use in their engines, but do not recommend using a fuel such as E8585.
There are no mass-produced outboard engines analogous to the FFV in the automobile
81 State of Wisconsin, National Ethanol Vehicle Coalition, General Motors Kick-off Multi-State E85 Public Awareness Campaign, 16 July 2003, General Motors, 17 Oct. 2003, < http://www.gm.com/company/gmability/environment/news_issues/news/e85_awareness_071603.html>. 82 What is Ethanol?, Alternative Fuels Data Center, 17 Oct. 2003, <http://afdc.nrel.gov/altfuel/eth_general.html>. 83 Estimated Number of Alternative-Fueled Vehicles in Use in the United States, Sept. 2002, Energy Information Administration, 17 Oct. 2003, <http://www.eia.doe.gov/cneaf/alternate/page/datatables/table2.html>. 84 Estimated Consumption of Vehicle Fuels in the United States , Sept. 2002, Energy Information Administration, 17 Oct. 2003, <http://www.eia.doe.gov/cneaf/alternate/page/datatables/table10.html>. 85 Ethanol Use in Two and Four Cycle Small Engines, KL Process Design Group, 17 Oct 2003, <http://www.klprocess.com/2cycleeng.htm>.
Ethanol as Fuel for Recreational Boats Final Report
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industry; thus there is little to no demand for marine use of E85. Several tests have been
run using ethanol blends as fuel in small engines (outboard engines), and the ethanol
blends were found to perform comparably to normal gasoline.
VI. Engine Choice Justification
Four-stroke engines were focused upon for the proposed ethanol modification for
a number of reasons. These include the ease of modification due to carburetors (as
opposed to fuel injection), oil compatibility with ethanol, and relevance to today’s
boating market.
The primary problem with two-stroke engines is that the fuel is mixed with the
lubricating oil in the ignition chamber; both are vaporized, and this leaves the oil film on
the components in the chamber. However, this oil will not mix well with ethanol. It has
been suggested that different oil, such as biodiesel, could be used in place of two-stroke
oil, and would be compatible with ethanol86. Unfortunately, there are very limited studies
on this issue and the evidence for and against are inconclusive.
When dealing with engine conversion to ethanol, the primary modification
involves the air to fuel ratio. Ethanol runs richer than gasoline due to its lesser energy
content (a 9-1 ratio compared to a 14-1 ratio); thus the amount of fuel entering the
cylinder must be increased87. This requires mechanical modifications when dealing with
a carbureted engine; however fuel injection is another story. Electronic fuel injection
requires changing the programmed ratio and sensors to determine the appropriate amount
of fuel and air; something that is quite difficult to do at the retrofitting stage. This
86 Robert Warren, Two Stroke Engines and Ethanol, 16 Sept. 2000, 20 Nov. 2003, <http://archive.nnytech.net/sgroup/BIOFUEL/428/>. 87 Keat B. Drane, Convert Your Car to Alcohol, 1980, Love Street Books, 20 Nov. 2003, <www.journeytoforever.org/biofuel_library/ethanol_drane.html>.
Ethanol as Fuel for Recreational Boats Final Report
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modification can be very expensive and would require professionals with specialized
equipment; thus it is not feasible to retrofit a fuel-injected engine to run on ethanol at a
moderate cost88. However, the carburetor changes are relatively inexpensive, and can be
performed by a person with limited mechanical experience.
Perhaps the most important reason for using four-stroke engines for our
modification involves today’s outboard engine marketplace. We decided to focus on
smaller horsepower engines for two reasons. First, as the project was specific to
freshwater lakes, we found that the horsepower used on lakes is usually less than that on
the ocean. Second, as we are to be performing an engine modification, we had to be
conscious of our project budget. A large horsepower engine of 90hp or above could
command upwards of $10,000, and with a budget of only $1000, we decided that we
would focus on small engines out of necessity.
Small outboard engines differ from larger engines in that much of the state of the
art technology, such as direct and programmed fuel injection, is only in place for large
technologies, such as electronic fuel injection or carburetors. In fact, there are virtually
no two-stroke outboard engines less than 90 horsepower which have fuel injection,
electronic or direct (see Appendix I). They instead have the high polluting carburetors,
which allow large amounts of gasoline to be unburned and released into the water and
atmosphere. Because of this, several areas in California have begun to ban all carbureted
two-strokes on their lakes89. This action has led to the gradual phasing out of small
horsepower two-strokes, and the general acceptance of four-stroke alternatives. The 88 Jay Kidwell, “ethanol boats”, The Carburetor Shop Inc., e-mail to the author, 28 Nov. 2003. 89 Tahoe Regional Planning Association, Environmental Assessment for the Prohibition of Certain two-stroke Powered Watercraft, 19 Jan. 1999, 20 Nov. 2003, < www.trpa.org/Boating/MWC%20EA.pdf>.
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primary concerns regarding four-strokes are their increased weight, somewhat lesser
performance, and higher cost relative to two-strokes90. However, while this is a large
concern for high performing, heavy, and expensive large engines, for smaller engines
these concerns can be overcome. As the technology has improved, the weight,
performance, and cost of four-strokes has begun to approach those of two-strokes in the
lower horsepower classes91. Thus, it appears that the future of carbureted two-stroke’s
are limited. In fact, some manufacturers such as Suzuki no longer produce two-strokes
below 150 horsepower; instead they use four-strokes for their low to moderate
horsepower engines92.
For these reasons, four-strokes were chosen as the engine of choice for our study
of ethanol’s use in small horsepower outboard engines. Keep in mind, however, that the
modifications given for the four-stroke engine could be readily applied to the carbureted
two-stroke, with the only major difference the ethanol-compatible engine oil. See
Appendix J for information regarding two-stroke ethanol-compatible engine oil.
The Four-Stroke Engine
The four-stroke outboard engine has a number of aspects which must be
considered when undertaking a modification for ethanol use. The first is to note the
differences in four-stroke outboard and automotive engines. While similar, the outboard
engine lacks many of the sophisticated pollution control measures of the automotive
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Another important consideration is the method of fuel induction. As discussed
above with regards to two-strokes, smaller models tend to have carburetors, while larger
models have electronic fuel injection. This holds true for four-stroke models as well;
however, there is one important consideration. While the difference between carbureted
and direct injected two-strokes is great (carbureted models do not pass EPA 2006 and
CARB 2004 standards), all four-strokes manufactured today, regardless of fuel induction
method, surpass these standards93. Thus, while electronic fuel injected models are
somewhat cleaner and more energy efficient, the gap between the two technologies is
much less than with two-strokes. This is important, as research has shown that similar to
two-strokes, all four-strokes below 30 horsepower are carbureted. In fact, the majority of
four-strokes below 90 horsepower are carbureted; however, a few select manufacturers
have begun to offer both electronically fuel injected and carbureted models in the 30-90
horsepower range (See Appendix I). As discussed earlier, we are focusing on small
horsepower models (5-15 horsepower), and thus on carbureted four-stroke engines.
VII. Engine Modifications Necessary for Ethanol Operation
There are two main categories of the engine modifications needed to allow for
ethanol use as a fuel. These modifications are necessary for ethanol combustion and
sustainability, and to optimize the engine for ethanol use. The modifications discussed
here are general changes needed for engine components present in most four-stroke
engines.
First, we discuss the minimal modifications needed to run an engine on ethanol.
The first modification is to ensure that the fuel tank, fuel lines, and carburetor are all 93 State of California Air Resources Board, Emission Standards and Test Procedures for New 2001 and Later Model Year Spark-Ignition Marine Engines, Oct. 1999, 20 Nov. 2003, < http://www.arb.ca.gov/regact/marine/fsor.pdf>.
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compatible with ethanol. This is primarily only a problem with older engines, as all
current engines in the US are guaranteed to run on ethanol blends. However, certain
plastic components like fuel filters should be replaced with glass alternatives.
Additionally, rubber is particularly sensitive to ethanol, and should be replaced with
Viton94. Assuming all the components are compatible with ethanol, the next step is
actual modifications to the engine. These primarily involve changes to the carburetor
used to supply the fuel-air mixture to the engine. First, the main jet, which allows fuel to
mix with the air, needs to be enlarged. Because ethanol contains a certain amount of
oxygen, this allows it to run richer than gasoline, and therefore a higher fuel to air ratio is
needed. This can be accomplished by enlarging the main jet approx. 27%95. For our
engine, we will likely purchase a carburetor rebuild kit, which will have specifications
and replacement parts for our carburetor96. Using that, we can purchase multiple jets, and
have each jet a different size (an increase of anywhere from 20-40% of the original size).
We can then undergo testing to determine which size results in the optimum performance.
This can be done by ensuring that the engine is firing correctly without ‘pinging’, and
also that the spark plugs do not become white due to excessive heat. Additionally, the
idle orifice and the accelerator pump nozzle may also need to be enlarged, depending on
the specific carburetor97.
94 Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998, 19-33. 95 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 96 Keat B. Drane, Convert Your Car to Alcohol, 1980, Love Street Books, 20 Nov. 2003, <www.journeytoforever.org/biofuel_library/ethanol_drane.html>. 97 Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, < http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>.
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Another important modification involves altering the ignition timing. While
gasoline engines ignite near or at the top of the piston stroke, ethanol can have a much
earlier ignition, due to its increased vaporization time. This is accomplished by turning
the distributor housing opposite the rotor direction. While studies have shown ethanol
utilizes a 10-24 degree turn opposite the rotor direction, it is necessary to experiment with
various degrees to optimize the particular engine and prevent knocking or pinging98.
The second group of modifications is those used to optimize the engine for
ethanol; that is increasing fuel efficiency and power output. The primary modification
here involves altering the compression ratio to maximize ethanol’s efficiency. The
compression ratio of a gasoline engine is around 8.5 to one; however ethanol can tolerate
10 or 11 to one99. The two primary methods of altering the compression ratio are using
modified pistons designed for high compression ratio, or milling the cylinder head
down100. The purchase of a new piston is obviously preferred, but for the purposes of
retrofitting an outboard engine, the cost is a major deterrent. Depending on the type of
engine and the desired increase in compression ratio (quite large in the case of ethanol),
the price can range from $50 to $1000 for a high compression piston. This would suggest
the second method might be more feasible, however milling the piston can potentially
interfere with normal engine operation, and may only slightly increase the compression
98 Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>. 99 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 100 Stephen P. Mullen, Compression Ratios, 2003, Night Rider.com, 20 Nov. 2003, <http://www.nightrider.com/biketech/hdhead_compression.htm>.
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ratio (0.5 to 1 points)101. Thus, altering the compression ratio for ethanol is a luxury that
those with sufficient resources can explore; however to the average outboard boat owner,
altering the compression ratio is not necessary. For our project, it will be useful to
explore the potential to increase the compression ratio, however this is not practical until
the actual engine is obtained, due to the wide variation in piston types and costs from
manufacturer to manufacturer. This is the primary difference between retrofitting a
gasoline engine to run on ethanol and designing an ethanol engine in the production
stage; during production ethanol’s efficiency and performance can be optimized at
minimal cost by using a different piston to increase the compression ratio; however,
during the retrofitting stage altering the compression ratio is more difficult and
potentially quite costly.
IX. Modifications to the Outboard Engine
Jet Design
In order to increase the fuel to air ratio, the main jet’s diameter needed to be
enlarged. A study provided by the Mother Earth News recommended that the diameter
be increased by 20% to 40%102. Below is the Pro/ENGINEER drawing of the main jet
with the original diameter.
101 Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>. 102 < Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>.
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Figure 2. Original Main Jet
The original plan was to enlarge the diameters by the following increments: 20%,
25%, 30%, 35%, and 40%. Unfortunately, the manufacturer only provided three jets, so
the dimensions used were: 0.033” (20% increase – drill #66), 0.036 (30% increase – drill
# 64), and 0.039” (40% increase – drill # 61). See Appendix M for the Pro/E drawing of
the side-view of the jet and the corresponding nozzle.
Materials Ethanol Compatibility
In terms of materials compatibility, the literature research suggested compatibility
issues in using ethanol fuel in an engine designed for gasoline. In particular, ethanol can
affect rubber, plastic and metal parts. Because the ethanol would only be in contact with
the fuel system, the following compatibility issues were identified: fuel line tubing and
o-rings (rubber), the fuel filter (plastic), the fuel pump (plastic, rubber, and some metal),
and the carburetor/main jet (metal).
To solve the compatibility issue with the tubing and o-rings, the material of the
existing tubing and o-rings needed to be determined. Unfortunately, as this information
is considered proprietary, Mercury Marine was unable to offer this data. Because the
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engine’s manual discourages the use of fuel with more than 10% ethanol, it was
determined that these parts should be replaced. To analyze the effect that ethanol would
have on the rubber, the tubing and o-rings were measured and submersed in ethanol to
determine whether corrosion or deformation would occur. After 17 days of soaking, the
resulting ethanol was slightly discolored for both the tubing and the o-rings. Upon
measurement after the soaking, it was determined that very little change to the parts
occurred in the given time period. This is consistent with current research, as it may take
a period of months to see any drastic changes. Thus, an alternative material was
investigated.
Several ethanol-friendly replacements exist as a material replacement. One study
suggested Viton (Fluoroelastomer-Terpolymer). Upon further investigation, Viton was
determined to be a suitable replacement for ethanol contact103. See Appendix N for
further information on ethanol’s compatibility with rubber. Viton GF tubing with the
same inner and outer diameter was purchased for replacement. The tubing was then cut
to proportions similar to the rubber fuel lines and put into place as depicted in blue
below.
103 Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998.
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Figure 3. Tubing in Fuel System
Three o-rings potentially come into contact with the fuel. They are located at the
intake manifold, between the fuel pump and cylinder, and on the drainage screw of the
carburetor. Butyl rubber was recommended by American Seal, Inc. as the viable
replacement material. However, because the ordered o-rings arrived with the incorrect
diameter and because one o-ring could only be specially ordered at high cost, the o-rings
were not replaced. The analysis of how ethanol affected the o-rings suggested that
drastic corrosion would not occur over short time intervals. It is also important to note
that leakage was not apparent near these o-rings, further suggesting that the seal was
maintained and that corrosion may not drastically affect these parts within the time frame
of the project.
Much like the rubber parts, the type of plastic for the fuel filter was
undeterminable. A similar strategy was implemented where the fuel filter was measured
and soaked in ethanol to determine whether corrosion or deformation would occur. In the
17 days of soaking, there was no visible change to the filter. In addition, with a minimal
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replacement cost direct from Mercury, the filter was determined to be able to run in the
short term and could easily be replaced if corrosion was to occur.
No degradation of the fuel pump was observed while the engine ran on ethanol
through the course of this study. EDS (energy-dispersive x-ray spectroscopy) using a
Scanning Electron Microscope revealed that the fuel pump is composed primarily of
aluminum and zinc-aluminum alloys. According to the Aluminum Association,
anhydrous ethyl alcohol was corrosive to aluminum alloys, but alloy 3003 was resistant
to aqueous solutions of ethanol. Additionally, “aluminum alloys have been used
commercially for stills, heat exchangers, drums, tanks, and piping in the processing of
ethyl alcohol and products employing ethyl alcohol in their manufacture.”104
There exists the possibility that the current fuel pump is not compatible with
ethanol. The effects of ethanol on the pump should be further investigated, particularly
looking at the effects of ethanol on the body and the diaphragm. If there is evidence of
galvanic corrosion on the aluminum, a gold coating could be used to anodize the
aluminum, creating a layer of aluminum oxide. This would protect the underlying layers
of aluminum from being oxidized.105 Alternatively, ethanol-compatible fuel pumps exist
for higher horsepower engines. For example, the smallest ethanol-compatible ones
available from Summit Racing are the Holly 140 GPH (gallons per hour) fuel pump and
the Mallory 110 GPH fuel pump. These pumps would normally be used on a 550-
104Warren Hunt, “Re: ethanol and aluminum,” Aluminum Association Technical Information Service, email to the author, 23 Feb. 2004. 105 Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998.
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horsepower engine.106 Because ethanol-compatible fuel pumps exist for more powerful
engines, should a demand arise for less powerful ones, they could be readily developed.
Also, the primary material in the main jet was identified as brass. The EDS plots
for main jet and fuel pump are in Appendix O. For the carburetor, the metal was
undeterminable, as there was not material to remove for use with EDS. However,
research findings to this date did not indicate materials compatibility issues for
carburetors. Further, in taking apart the carburetor to change main jets, no evidence of
corrosion was seen where the carburetor comes in contact with fuel.
Cold Start Solutions
Perhaps the greatest obstacle to ethanol-fueled vehicles is their difficulty to start
in cold conditions. Due to the higher latent heat of vaporization and lower Reid vapor
pressure of ethanol, when the temperature drops below 11 degrees Celsius, the engine has
difficulty starting as there is not sufficient vaporization of the ethanol107. Several
solutions have been proposed to deal with this problem in automobiles; however use in
outboard engines provides a few additional challenges.
The majority of the solutions center on using an alternative fuel to ‘prep’ the
engine by heating it, then allowing the ethanol to take over. The fuel obviously needs to
have a much lower latent heat of vaporization, so that cold starting is not an issue. There
are a few other solutions proposed which consider the preheating of the ethanol fuel for
use in the engine; most of these involve the use of electricity. One aspect unique to
boating is that while automobiles in cold climates frequently can be in use in extremely
106 Lance Besse, Summit Racing, phone conversation with the author, 5 March 2004. 107 Dr. Gregory W. Davis, Development of Technologies to Improve Cold Start Performance of Ethanol Vehicles, 11 June 2001, Kettering University, 20 Nov. 2003, <http://www.michiganbioenergy.org/pubs/coldstart.pdf>.
Ethanol as Fuel for Recreational Boats Final Report
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cold temperatures, it is unlikely that a boat will be used for recreational purposes in
extreme cold. If the temperature drops below freezing, boaters run the risk of ice forming
on the lake, not to mention the frost and wind chill associated with cold weather boating.
Thus, while the cold start ability is important in the event of boating in sub 11 degree
temperature, this use is assumed to be infrequent, and the temperature to be relatively
moderate (above freezing). Additionally, for automobiles in extremely cold climates, the
ethanol fuel may need to be preheated throughout operation, by rerouting the exhaust or
another heat source. However, recreational boat operation is very unlikely in extreme
cold, and thus this modification is not necessary.
There are several factors which are to be considered in choosing a system for cold
starting an ethanol run engine.
• Portability – This is important in marine use, unlike automobiles, as it is not always possible to drive up to the fuel source, and the fuel may have to be transported to the boat.
• Availability – As many lakes for recreational use are located in remote locations, the fuel should be widely available.
• Fuel Cost - The fuel or method of heating should not be overly expensive, and at worst be comparable to ethanol.
• Retrofit Cost – The cost of the cold start system should be minor. • Effectiveness – The engine should start quickly • Repeatability – The cold start should work multiple times over a usage period • Environmental Impact – The cold start method should not be significantly high
polluting. This is of lesser importance, due to the aforementioned rare use of marine cold start.
• Ease of Use – As many recreational boat users have limited knowledge of outboard motor mechanics, the cold start solution should be simple to use.
The proposed solutions to the cold start problem can be broken into two
categories, various fuels and electrical heating. The fuels will be combusted for a few
seconds, heating the chamber to allow for the combustion of ethanol. The electrical
heating will heat the carburetor or fuel line to preheat the ethanol before entering the
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combustion chamber. The different fuel options include propane, gasoline, natural gas,
hydrogen, diethyl ether from ethanol, and diethyl ether starting fluid. The electric options
include an outlet powered electric heater, and a battery powered one.
We ranked the eight potential solutions for each of the eight factors, and created a
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An examination of this above matrix reveals a tie for the most optimal jet size for
ethanol combustion. Thus, it is likely that the true ideal value lies somewhere in between
the two values. However, for the purposes of this paper the 0.033” diameter was chosen
as the ideal jet size, as the emissions gains demonstrated by this jet size were more than
double the 0.036” diameter, while the efficiency loss was only 15%.
XII. Economic Analysis of Engine
After the engine was modified to run on ethanol, the overall retrofitting cost must
be determined and compared to the target overall cost described in the project
specifications. For the project purposes, the overall cost of retrofit was determined to
include the cost of ethanol compatible materials, the cost of the labor, to alter the jet
diameter sizes, and to replace the materials. For the purposes of comparison with the
target specifications, the labor cost was not included, as the modifications made were
readily done without the aid of a specialist.
Replacement of the rubber fuel lines to Viton tubing had no associated cost,
because the Viton was donated by the supplier. However, in most cases there would a
cost in acquiring the ethanol-compatible tubing. According to the supplier, the minimum
order of tubing is $25, which provides more than enough tubing necessary to replace all
fuel lines. If the fuel lines are replaced by a professional, a labor cost would also be
incurred. Thus, the overall cost of materials replacement would be $25 without labor
costs. This value can be further reduced if the Viton is purchased in bulk and used in
multiple retro-fits.
The original modification design also called for a change in the o-rings. Although
this modification was not completed, the potential cost is explained for the engine
economic analysis. The replacement o-rings of butyl rubber, type 116 and 217, need to
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be ordered at a cost of $2.50 and $6.18, respectively. A smaller o-ring, not commonly
held in stock by suppliers, would need to be specialty ordered at a minimum of 1,180
pieces at $38 per 100 pieces. Although this constraint made this modification infeasible,
given a demand, this o-ring would merely add to the overall cost of about $0.38. Thus,
the overall cost of engine modification would be increased by $9.06.
If the modifications are done by an outside professional, a labor cost would also
be incurred. According to Fairlee Marine, the cost to replace all the fuel lines and o-rings
with already purchased materials would take approximately one hour, charged at $45 per
hour. With labor costs, the overall materials replacement would cost $79.06.
To change the jet size, no additional parts are necessary, as the optimum jet size
for ethanol can be drilled from the existing jet. For this reason, only a labor cost is
associated with this modification. Depending on the user’s level of experience, a cost
may or may not be incurred. According to the Thayer School Machine Shop, the jet size
alteration on a drill press would take one hour, charged at $60 per hour. For the project’s
purposes, the drilling was done at no charge, but would potentially increase the overall
cost by $60, to an overall cost of $139.06.
Modification Cost without
Labor Cost with Labor
Tubing $25.00 $25.00
O-ring $9.06 $9.06 Labor $0.00 $45.00
Jet Size $0.00 $0.00
Labor $0.00 $60.00
TOTAL $34.06 $139.06
Table 11. Engine modification costs with and without labor.
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XIII. Discussion of Specification Results
After completion of the ethanol engine testing, the results can be compared to the
original target specifications.
Area Target Specification Actual Specification % Deviation from Specification (if does not satisfy)
Environmental NOx + HC emissions
<1770.8 PPM 819.5 PPM
CO emissions <0.85% (reduction by 10%)
1.03% 21.2%
Performance Horsepower >5 hp (100% of
running on gasoline – no compression ratio change)
5.06 hp
Efficiency At least 0.140 gal/hr-hp (at least 66.7% of gasoline)
0.142 gal/hr-hp
1.4%
Cold-start Must start above 30°F
Started above 30°F
Weight < 62.7 lbs. (110% of original engine weight)
57 lbs.
Economics Overall cost to retrofit (excluding labor)
<$250 (25% of engine value maximum)
$34.06
Table 12. Specifications Assessment
In general, our ethanol engine satisfied the majority of the target specifications.
Exceptions were in CO emissions and efficiency; however, the efficiency result was very
close to the target specification (within 2%). One possible explanation for the CO
emissions is that the engine was not optimized to run on ethanol (through ideal air-fuel
mixture), resulting in incomplete combustion. If, however, the engine were to be
optimized, it would appear that the engine would meet the specification. This is
illustrated in Appendix Q, where a comparison between the emissions at idling speed is
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presented. At the idle speed, the engine was optimized by altering the idle screw,
resulting in a significant decrease in CO emissions while operating on ethanol.
XIV. Marketability
Examining the results of the specifications previously discussed, several
conclusions can be drawn with respect to the overall marketability of the ethanol-fueled
outboard engine. It is clear that a small four-stroke outboard engine can be converted to
run on ethanol fuel with no loss in horsepower with reduced hydrocarbon emissions.
Additionally, the cost of retrofitting such engine is relatively minor, and it is feasible to
think that on a manufacturing level the conversion to ethanol could be done at no
additional cost to the consumer. However, the primary specification where ethanol loses
points in marketability is with regards to fuel efficiency. Ethanol requires approximately
1.5 times as much volume to achieve the same power output as gasoline. This results in
shorter operating time for a tank of fuel and higher costs due to the increased frequency
of refueling. For example, with the average gasoline and ethanol costs previously
calculated, the cost of using ethanol fuel would be approximately 46% more than using
gasoline. With an average yearly consumption of 60 gallons of gasoline (for an average
boater), an increase in yearly fuel costs from $101 to $141 could be expected. The
recreational boating community may find this to be a serious deterrent to using an
ethanol-fueled engine.
These observations were supported through contacting members of the boating
community, policymakers in California, and ethanol organizations. The majority of the
responders were encouraged by the possibility of an alternatively fueled outboard engine,
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but expressed many of the same concerns. Randy Stratton of The Stratton Group, Inc.
commented on the marketability:
The buying public always looks towards mainstream success for their purchasing decision. If a product has had success and proven to perform at or near that of a gasoline powered engine, they will most certainly consider it. If there are benefits that outweigh the extra costs – consumers will weigh the benefits based on their own value system, their environmental awareness and the role it plays in creating additional dollar value here in the U.S.113
Chris Virgo, a mechanic at North Tahoe Marina, said that although there are a lot of
environmentally-conscious people, they are not willing to pay anything extra. Also, he
explained that boaters are currently resistant to the Lake Tahoe regulations requiring
them to give up their carburetated two-strokes.114 Jackie Lourenco at the California Air
Resources Board said that the only way that a new outboard would be marketable is if it
drastically reduced hydrocarbon and NOx emissions.115 Unfortunately, the attempts to
contact major outboard engine manufacturers were unsuccessful.
XV. Conclusions and Recommendations for Future Studies
Ethanol has been shown to be a viable alternative to gasoline for use in
recreational boat engines, due to ethanol’s better environmental performance as a fuel
over gasoline. Given the finite supply of fossil-based energy, alternatives to petroleum
are an increasingly important consideration. Ethanol is particularly advantageous in the
niche market of recreational outboard engines, and this study has proven the ability to
retrofit an engine with minimal modifications and lose little in the way of performance.
However, there is still much to be done before ethanol becomes a widespread alternative
to gasoline in outboard engines.
113 Randy Stratton, The Stratton Group, Inc., “RE: ethanol-powered outboard,” 4 March 2004. 114 Chris Virgo, North Tahoe Marina, phone conversation with the author, 5 March 2004. 115 Jackie Lourenco, California Air Resources Board, phone conversation with the author, 4 March 2004.
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Further studies on horsepower testing using a dynamometer would aid in
supporting our data, and more specific emissions testing by government regulators such
as CARB would also help illustrate the advantages of using ethanol as a fuel.
Additionally, a future study could include larger four-stroke engines, multiple fuel
induction methods such as direct and electronic fuel injection, and even two-stroke
engines pending the determination of ethanol-compatible engine oil. This would expand
the potential market for ethanol outboard engines to include the entire boating industry,
rather than the specific niche of small, carbureted four-stroke engines.
A potential advantage of ethanol over gasoline which could be explored is the
issue of noise pollution. Many lake communities have problems with the high noise
levels due to boat traffic; however, in the testing of this study, it was observed that the
use of ethanol reduced the decibel levels produced by the engine operation as compared
to gasoline.
Future studies could also be conducted in determining the ideal air-fuel ratio for
ethanol combustion; where this study narrowed the range to 20-30% for our engine,
additional testing could pinpoint the exact ratio so as to further optimize combustion.
Furthering this optimization, advancing the ignition timing and increasing the
compression ratio at the manufacturing level could further optimize the engine, perhaps
resulting in increased power offsetting the loss in fuel efficiency for ethanol.
Finally, studies in the materials compatibility of many of the metals present in the
engine, such as aluminum, would help support the longevity of the engine. Replacing
such components as the fuel pump and fuel filter with cost-effective ethanol alternatives
Ethanol as Fuel for Recreational Boats Final Report
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would allow an ethanol-fueled engine to have the same reliability and durability of its
gasoline counterpart.
In conclusion, this study has demonstrated the significant benefits of using
ethanol as a boating fuel. Given the mentioned recommendations, the case for ethanol’s
viability as a fuel in recreational boating will be strengthened. Furthermore, the
successful introduction of ethanol into boating applications may lead to the use of ethanol
as a fuel in a much broader context.
XVI. Acknowledgements
The authors would like to express their gratitude to the following people: At Thayer School:
Professor Charles Wyman Professor John Collier Professor Robert Graves Doug Fraser Gary Durkee Thayer School Instrument Room Thayer School Machine Shop Paula Berg Professor Benoit Cushman-Roisin Professor Horst Richter Joan Levy Cathy Follensbee William Cote Bin Yang Daniel Iliescu Daniel Cullen
Outside sources:
Fairlee Marine Betsy Dorries and Steve Belitsos at Vermont Technical College Roberta Nichols Terry Jaffoni and Jackie Fee of Cargill Michael O'Keefe and Professor Phil Malte at University of Washington Don Mathey at Donlee Pump Company California Air Resources Board Environmental Protection Agency (especially Stout Alan) Edward Nelson at Wisconsin Department of Natural Resources
Ethanol as Fuel for Recreational Boats Final Report
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Tom Durbin at University of California Riverside Warren H. Hunt of the Aluminum Association Garland Lewis at Tohatsu John Cruger-Hansen Jeff Schloss at University of New Hampshire Jack Hull at Rainbow Rubber Extrusions Jay Kidwell at The Carburetor Shop, Inc. and Mile High Performance Bones Gate Fraternity Zeta Psi Fraternity
XVII. List of Works Cited
Robert Warren, Two Stroke Engines and Ethanol, 16 Sept. 2000, 20 Nov. 2003, <http://archive.nnytech.net/sgroup/BIOFUEL/428/>. Keat B. Drane, Convert Your Car to Alcohol, 1980, Love Street Books, 20 Nov. 2003, <www.journeytoforever.org/biofuel_library/ethanol_drane.html>. Jay Kidwell, “ethanol boats”, The Carburetor Shop Inc., e-mail to the author, 28 Nov. 2003. Tahoe Regional Planning Association, Environmental Assessment for the Prohibition of Certain 2-Stroke Powered Watercraft, 19 Jan. 1999, 20 Nov. 2003, <www.trpa.org/Boating/MWC%20EA.pdf>. AFA Marine Inc., 4-Stroke Outboard Motor vs. 2-Stroke Outboards, Oct. 2002, 20 Nov. 2003, <http://www.smalloutboards.com/4Stroke.htm>. Mercury Marine, Technology & Water FAQ’s, 20 Nov. 2003, <http://www.mercurymarine.com/technology__water>. Suzuki Marine, 2003 2-Strokes, 20 Nov. 2003, < http://www.suzukimarine.com/2strokes/>. State of California Air Resources Board, Emission Standards and Test Procedures for New 2001 and Later Model Year Spark-Ignition Marine Engines, Oct. 1999, 20 Nov. 2003, <http://www.arb.ca.gov/regact/marine/fsor.pdf>. Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998, 19-33. Fairlee Marine, telephone conversation with author, 4 Dec. 2003. Becky Ohler, New Hampshire Department of Environmental Services, telephone conversation with the author, 4 Dec. 2003.
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Doug Fraser, Dartmouth College Thayer School of Engineering, conversation with the author, 4 Dec. 2003. Douglas Elliott, State of Vermont - Air Pollution Control Division, telephone conversation with the author, 4 Dec. 2003. Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>. Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, <http://terrasol.home.igc.org/alky/alky2.htm>. Stephen P. Mullen, Compression Ratios, 2003, Night Rider.com, 20 Nov. 2003, <http://www.nightrider.com/biketech/hdhead_compression.htm>. Dr. Gregory W. Davis, Development of Technologies to Improve Cold Start Performance of Ethanol Vehicles, 11 June 2001, Kettering University, 20 Nov. 2003, <http://www.michiganbioenergy.org/pubs/coldstart.pdf>. Tomoko Kito and Scott Cowley, Generation of Diethyl Ether in an Ethanol Vehicle System for Cold-Start Assistance, 22 Nov. 1996, Colorado School of Mines, 20 Nov. 2003, <http://www.mines.edu/research/cifer/research/coldstart.html>. Nautical Know How Inc., Marine Battery Primer, 28 Aug. 2000, 20 Nov. 2003, <http://www.boatsafe.com/nauticalknowhow/marine_battery.htm>. The Australian Greenhouse Office, Australian Government <www.greenhouse.gov.au/transport/ comparison/pubs/2ch13.pdf> Nov 2003 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996). Alternative Fuels Data Center, Alternative Fuel Station Counts Listed by State and Fuel Type (Dept. Of Energy 1 Dec. 2003), <http://www.afdc.doe.gov/refuel/state_tot.shtml>. Minnesota Pollution Control Agency, June 2003 <http://www.pca.state.mn.us/air/toxics/toxics-graphs.html>. US EPA, Polluted Runoff (Non-Point Source Pollution), August 2003 <http://www.epa.gov/owow/nps/>.
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MFA Oil Material Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm>. Material Safety Data Sheet-Chevron, Regular Unleaded Gasoline <http://library.cbest.chevron.com/lubes/chevmsdsv9.nsf/0/8002e031e024ef378825620c 000c2616?OpenDocument>. MFA Oil Material Data Sheets, Unleaded Gasoline. US EPA, Groundwater and Drinking Water, Technical fact sheet: benzene, Nov. 2002 <http://www.epa.gov/OGWDW/dwh/t-voc/benzene.html>. Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 2001) 375. Nancy E. Kinner, Testimony before the U.S. Senate Committee on Environment and Public Works, University of New Hampshire, April 23, 2001. US EIA, Status and Impact of MTBE bans, March 2003 <http://www.eia.doe.gov/oiaf/servicerpt/mtbeban/table1.html>. US Dept. of Health and Human Services. “Carbon Monoxide Emissions and Exposures on Recreational Boats Under Various Operating Conditions” Feb. 2003 <safetynet.smis.doi.gov/Report%20171-05ee2.pdf>. US Water News Online, “Experts study effects of Sacramento pollution on Lake Tahoe” Sept 2003. <http://www.uswaternews.com/archives/arcquality/3expstu9.html>. Government of Canada, Canada and the Kyoto Protocol, July 2001, viewed 10/17/03 <http://www.climatechange.gc.ca/english/whats_new/overview_e.html>. US EPA, Air trends summary: PM-10. April 2002. <http://www.epa.gov/air/aqtrnd95/pm10.html>. William W. Nazaroff and Lisa Alvarez-Cohen, Environmental Engineering Science, (New York: John Wiley & Sons, Inc, 2001) 282. Powers, Susan, et al. “Transport and fate of ethanol and BTEX in groundwater contamination by gasohol” 2000. AEA Technology. “Ethanol Emissions Testing” March 2002. Alternative Fuels-alternative drive trains, Nov. 2003 <http://www.altfuels.org/backgrnd/altdrive.html>. PC Chem Material Safety Data Sheet, Ethanol
Ethanol as Fuel for Recreational Boats Final Report
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<www.chemsupply.com.au/MSDS/1CH9O.pdf> US EPA ethanol fact sheet, Mar 2002 <http://www.epa.gov/otaq/consumer/fuels/altfuels/altfuels.htm#fact>. The Plain English Guide to the Clean Air Act, 1993, EPA – Air Quality and Standards, 28 Nov. 2003, <http://www.epa.gov/oar/oaqps/peg_caa/pegcaain.html>. The Clean Water Act, 2003, EPA – Laws and Regulations, 28 Nov. 2003, <http://www.epa.gov/region5/water/cwa.htm>. Pollution Regulations, 2003, US Coast Guard, 30 Nov. 2003, <http://www.uscgboating.org/safety/fed_reqs/equ_pollution.htm>. Control of Air Emissions from Marine Spark-Ignition Engines, 2003, EPA – Air Programs, 31 Oct. 2003, <http://ecfrback.access.gpo.gov/otcgi/cfr/otfilter.cgi?DB=3&query=40000000091®ion=BIBSRT&action=view&SUBSET=SUBSET&FROM=1&SIZE=10&ITEM=1#Sec.%2091.101>. Emission Standards and Test Procedures for New 2001 and Later Model Year Spark-Ignition Engines, 1999, Air Resources Board, 25 October 2003, <http://www.arb.ca.gov/regact/marine/fsor.pdf>. California Code of Regulations, Chapter 9 Off-Road Vehicles and Engines Pollution Control Devices, section 2443.3 3. New Regulations for gasoline marine engines, 1999, Air Resources Board, 12 Nov. 2003, <http://www.arb.ca.gov/msprog/marine/facts.pdf>. A Consumer’s Guide to Lake Tahoe, Tahoe Regional Planning Agency, 12 Nov. 2003, <http://www.dbw.ca.gov/Pubs/Blt/>. California Energy Commission, Ethanol Supply Outlook for California (2003). Ethanol and Market Opportunities, 2000, RFA, 1 Nov. 2003, <http://www.ethanolrfa.org/factfic_market.html>. Downstream Alternatives, Inc., The Renewable Fuels Association, The Use of Ethanol in California Clean Burning Gasoline – Ethanol Supply/Demand (1999). Conversation with Professor Benoit Cushman-Roisin Dec. 12, 2003 Renewable Fuels Association, "Ethanol and the Environment" <http://www.ethanolrfa.org/factfic_envir.html>.
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Mark Yancy, The Investment Climate for Ethanol Production in California, 2003, BBI, 29 Nov. 2003, <http://www.bbiethanol.com/doe/ca/Yancey-CA-DOE.pdf>. Tax Rate on Ethanol or Methanol, 2003, Database of State Incentives for Renewable Energy, 29 Nov. 2003, <http://www.dsireusa.org/library/includes/incentive2.cfm?Incentive_Code=CA24F&state=CA&CurrentPageID=1>. John Cruger-Hansen, “Re: fuel docks,” email to the author, 15 Nov. 2003. Donlee Pumps, “Re: ethanol storage in marinas in CA,” email to the author, 2 Dec. 2003. Transportation Fuels: Gasoline, Diesel, Ethanol, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/index.html>. US Department of Transportation, United States Coast Guard, Boating Statistics – 2000 (2000). Department of Boating and Waterways, 2003, California, 4 Nov. 2003, <http://www.dbw.ca.gov/index.htm>. Power Boat Industry Statistics, Recreational Boat Building Industry, 7 Nov. 2003, <http://www.rbbi.com/desks/mkt/stats/stats.htm>. Stephanie Hussey, “Ethanol as a fuel for recreational boating,” email to the author, 19 Nov. 2003. Curley Andrews, “RE: gasoline consumption in boats,” email to the author, 17 Nov. 2003. Answers, “RE: gasoline consumption in boats,” email to the author, 17 Nov. 2003. Eugene Lange, “Gasoline Consumption Estimate for the 2000 Recreational Boating Survey,” State of Wisconsin – Department of Natural Resources. 2002. Edward Nelson, “RE: gasoline consumption in boats,” email to the author, 20 Nov. 2003. Tahoe Regional Planning Agency, Environmental Assessment for the Prohibition of Certain Two-Stroke Powered Watercraft (1999). Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished. Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000. 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>.
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Tax Incentives for Electric and Clean-Fuel Vehicles, 2003, Fueleconomy.gov, 9 Nov. 2003, <http://www.fueleconomy.gov/feg/tax_afv.shtml>. Tahoe Regional Planning Association, Environmental Assessment for the Prohibition of Certain 2-Stroke Powered Watercraft, 19 Jan. 1999, 20 Nov. 2003, <www.trpa.org/Boating/MWC%20EA.pdf>. Biomass Energy: Cost of Production, 2003, Oregon Department of Energy, 29 Nov. 2003, <http://www.energy.state.or.us/biomass/Cost.htm>. Outreach Projects: Alternative Fuel: Biodiesel, BoatU. S. Foundation, 16 Nov. 2003, <http://www.boatus.com/cleanwater/outreach/biodiesel.htm>. LNG (Liquefied Natural Gas) as a Fuel and Refrigerant for Diesel Powered Shrimp Boats, 2003, Centre for Alternative Fuels, 16 Nov. 2003, <http://catf.bcresearch.com/catf/catf.nsf/0/857BF7F61219213688256976006C3340?OpenDocument>. Wartsile LNG-Fuelled Engines for Offshore Vessels, Marine and Industrial Report, 29 Nov, 2003, <http://www.marinereport.com.sg/dec2001/wartsila.php>. About Natural Gas, NGV, 19 Nov. 2003, <http://www.ngvc.org/ngv/ngvc.nsf/bytitle/fastfacts.htm>. M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994). Clean Alternative Fuels: Compressed Natural Gas, 2002, EPA, 1 Dec. 2003, <http://www.epa.gov/otaq/consumer/fuels/altfuels/compressed.pdf>. Electric Drive Systems, Beckman Boatshop Limited, 29 Nov. 2003, <http://www.steamboating.net/electric.html>. Fuel Cells, 2003, 29 Nov. 2003, <http://www.boatsyachtsmarinas.com/bestsellers/html/fuel_cells.html>. First Hydrogen Fuel Cell Water Taxi on San Francisco Bay Powered by Anuvu, 2003, Yahoo! Finance, 29 Nov. 2003, <http://biz.yahoo.com/prnews/031016/sfth089_1.html>. Weekly Average Propane Prices, 2003, New York State Energy Research and Development Authority, 1 Dec. 2003, <http://www.nyserda.org/nyepf.html>. 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>.
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Graph of Ethanol Fuel History – 18 Months, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_18-month.html>. Graph of Ethanol Fuel History – Last Ten Years, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_10-year.html>. Vehicle Buyer’s Guide for Consumers, US Department of Energy – Energy Efficiency and Renewable Energy, 2 Dec. 2003, <http://www.ccities.doe.gov/vbg/consumers/how_much.shtml>. The Cost of Ethanol, C&T Brasil, 30 Nov. 2003, <http://www.mct.gov.br/clima/ingles/comunic_old/alcohol4.htm>. Warren Hunt, “Re: ethanol and aluminum,” Aluminum Association Technical Information Service, email to the author, 23 Feb. 2004. Lance Besse, Summit Racing, phone conversation with the author, 5 March 2004. Betsy Dorries, Vermont Technical College, personal communication to author, 21 Jan. 2004, 3 Mar. 2004. Summit, 5 March 2004, <http://www.summit.com/toolbox/techinfo/techdocs/motor-control.html>. Mercury Service Manual, 4/5/6 FourStroke, 2000. Randy Stratton, The Stratton Group, Inc., “RE: ethanol-powered outboard,” 4 March 2004. Chris Virgo, North Tahoe Marina, phone conversation with the author, 5 March 2004. Jackie Lourenco, California Air Resources Board, phone conversation with the author, 4 March 2004. William Mustain, Andrew Adamczyk. Determination of Plausible Fuel/Oil Mixtures for Two-Stroke Ethanol-Fueled Engines. 3 Apr. 2001. 20 Nov. 2003, <http://www.iit.edu/~ipro317/s01/Documents/Oil.pdf>. DuPont Dow Elastomers Chemical Resistance Guide, 2004. Garland Lewis, Tohatsu, “FW: Tohatsu,” email to author, 27 Feb 2004. Michael Moran and Howard Shapiro, Fundamentals of Engineering 4th Ed. (New York: Wiley, 2000).
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Appendix A. Comparison of Ethanol Fuel Properties to Gasoline116
Property Unleaded Gasoline Property Unleaded Gasoline Ethanol Description Volatile dark liquid with
a strong aroma Colorless liquid with alcohol
aroma Formula C4-C12 CH3CH2OH Molecular Weight 110 avg., 100-105 avg. 46.07 C, wt % 85 to 88 52.14 H, wt % 12 to 15 13.13 O, wt % Negligible 34.47 Density 690 to 800 g/L@20°C 789.3 g/L@20°C Freezing Point -40°C -114°C Atmospheric Boiling Point Latent Heat of Vaporization (per mass basis)
27 to 225°C 0.349 MJ/kg, (20°C)
78.5°C 0.839 MJ/kg (20°C)
Latent Heat of Vaporization (per volume basis)
0.251 MJ/L (20°C) 0.662 MJ/L (20°C)
Latent Heat (per mass of air for a stoichiometric mixture @ 15.6°C)
23.2 kJ/kg air 102.24 kJ/kg air
Flash Point -43 to -39°C 12.8°C Auto-ignition Point 257°C 423°C Flammability Limits, (Vol. % in Air)
1.4 to 7.6 4.3 to 19 % in air
Higher Heating Value (per mass basis)
47.2 MJ/kg @ 20°C avg. 29.8 MJ/kg@20°C
Higher Heating Value (per volume basis)
34.81 MJ/L 23.56 MJ/L
Lower Heating Value (per mass basis)
~43 MJ/kg avg. 27 MJ/kg
Lower Heating Value (per volume basis)
32.16 MJ/L @ 20°C avg. 21.09 MJ/L @ 20°C avg.
Viscosity 3.4 centipoise @ 20°C 1.19 centipoise @ 20°C Specific Gravity 0.750 @ 15.6°C 0.794 @ 15.6°C Stoichiometric AF Mass Ratio 14.7 8.97 Stoichiometric AF Volumetric Ratio
55 14.32
Water Solubility, wt% @ 20°C 0.009 Infinite Octane Number (R=research, M= motor)
88-98 (R), 90 to 100 (R), 82-92 (M), 81-90 (M)
111 (R), 108 (R), 96-113 ((R+M)/2), 92 (M)
Heat of Vap./LHV 0.0081 0.0343 Cetane Number <5 13 to 17 Reid Vapor Pressure 48-103 kPa @ 38°C 16 kPa @ 38°C Flame Luminosity (Relative to Gasoline)
100% 3%
Power Increase over Gasoline 0% 5%
Table 13. Comparison of Ethanol Fuel Properties to Gasoline
116 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000.
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Appendix B. Project Timetable
WEEK 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 TASKS ENGS 190 ENGG 290 Environmental Background research Investigate EtOH properties Investigate effects of gas/EtOH in lakes Investigate regulations Economic Case Study Background research Determine most applicable location Investigate infrastructure for fuel EtOH Investigate infrastructure cost Determine retail cost of EtOH on lakes Technical Background research Determine engine type Investigate engine modification for EtOH Investigate cold start technologies Evaluate literature research Search for and secure engine Written proposal Oral proposal Written progress report Oral progress report Pre-testing procedure and preparation Design retrofit for engine Benchmark testing for gasoline Materials acquisition for retrofit Construct prototype for ethanol Test ethanol prototype for performance Test ethanol prototype for emissions Cost analysis of retrofitted engine Investigate marketability of engine Implementation report via website Oral Progress Report Written Final Report Oral Final Report Legend Work Completed
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Appendix C. Alternative Fuels for Gasoline Marine Engines
In order to reduce pollutants from boats, there are only three viable alternatives:
man-powered, wind-powered, and finding a new fuel or power source. A fourth option
would be to completely redesign the engines for better gasoline or diesel efficiency, but
that would need to be done at the manufacturers’ level. The best option would be to
investigate alternative fuels and power sources. A variety of alternative ways for
powering motorboats have been applied – biodiesel, liquefied or compressed natural gas
(LNG or CNG), electricity, and fuel cells. Propane or alcohol fuels have not been used in
boating propulsion applications, but will be considered here.
Table 14. Alternative Fuels for Gasoline Marine Engines Matrix
Biodiesel is an alternative for using diesel in marine engines. Biodiesel was used
to fuel Bryan Peterson’s marine journey around the world in 1992-1994 and is being
considered for tour boats on Crater Lake in Oregon.117 The optimal blend is 20%
bodiesel/80% petroleum diesel (by volume). This particular blend will reduce emissions,
117 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000.
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improve lubricity, help clean injectors, fuel lines, pumps and tanks, and improve diesel
engine performance without requiring any modifications to the existing engines. Fuel
filters will need to be replaced more often, as the will clog more with the biodiesel fuel.
Also, the biodiesel blend has a higher cost per gallon - $1.10 per gallon with petroleum
diesel at $0.90 per gallon and soybean biodiesel at $1.80 per gallon.118 A greater than
20% blend would require some modifications as the biodiesel’s solvent properties would
react with certain types of rubber gaskets and hoses. In addition, biodiesel is safer to
store and transport than petroleum diesel as it has a higher flash point and is classified as
only combustible and not flammable or explosive.119 But, biodiesel can only be used in
engines designed to run on diesel and not gasoline.
Liquefied and compressed natural gas provide two more options for an alternative
to diesel as marine fuel. Diesel-powered shrimp boats have been adapted to run on dual
fuel – LNG and diesel with LNG providing 80% of the total heat addition at full load for
both engines.120 Wartsila Corporation produces LNG-fueled engines for offshore vessels,
which would lower NOx and CO2 emissions and have greater fuel efficiency.121 The fuel
tanks would have increased weight, volume and cost over conventional fuel tanks. These
fuels are typically applied towards large-scale marine applications, as the main
118 Biomass Energy: Cost of Production, 2003, Oregon Department of Energy, 29 Nov. 2003, <http://www.energy.state.or.us/biomass/Cost.htm>. 119 Outreach Projects: Alternative Fuel: Biodiesel, BoatU. S. Foundation, 16 Nov. 2003, <http://www.boatus.com/cleanwater/outreach/biodiesel.htm>. 120 LNG (Liquefied Natural Gas) as a Fuel and Refrigerant for Diesel Powered Shrimp Boats, 2003, Centre for Alternative Fuels, 16 Nov. 2003, <http://catf.bcresearch.com/catf/catf.nsf/0/857BF7F61219213688256976006C3340?OpenDocument>. 121 Wartsile LNG-Fuelled Engines for Offshore Vessels, Marine and Industrial Report, 29 Nov, 2003, <http://www.marinereport.com.sg/dec2001/wartsila.php>.
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advantages are seen in dedicated heavy-duty engines.122 Natural gas typically will cost
15% to 40% less than gasoline.123
Electric marine engines are designed to replace internal combustion engines.
They are typically only used on a small scale, although they can be used to produce high
speeds. Cruising range using electric drives are solely a function of the available battery
power and the discharge rate or boat speed. In practice it is often more feasible to
compromise speed for range and battery capacity for space. Electric drive systems are
particularly practical in boats that are easily pushed through the water – boats with
narrow beams, light displacement, and good hull design. Electric power for boat
propulsion is more efficient.124 But, they are not widely in use and the batteries are not
easily and quickly rechargeable125.
Fuel cells could provide pollutant-free marine transportation. Anuvu produced
the first hydrogen fuel cell-powered water taxi to be run on the San Francisco Bay in
October 2003. It only emits water vapor and heat.126 These fuel cells are best applicable
for government ferries and commercial marine fleets. They could be adapted for
recreational boating, but hydrogen fuel sources (needed to recharge the fuel cell) are not
readily available, other than in the form of fossil fuels.127 Also, hydrogen fuel cells are
still a very new technology.
122 M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994). 123 Clean Alternative Fuels: Compressed Natural Gas, 2002, EPA, 1 Dec. 2003, <http://www.epa.gov/otaq/consumer/fuels/altfuels/compressed.pdf>. 124 Electric Drive Systems, Beckman Boatshop Limited, 29 Nov. 2003, <http://www.steamboating.net/electric.html>. 125 Fuel Cells, 2003, 29 Nov. 2003, <http://www.boatsyachtsmarinas.com/bestsellers/html/fuel_cells.html>. 126 First Hydrogen Fuel Cell Water Taxi on San Francisco Bay Powered by Anuvu, 2003, Yahoo! Finance, 29 Nov. 2003, <http://biz.yahoo.com/prnews/031016/sfth089_1.html>. 127 Fuel Cells, 2003, 29 Nov. 2003, <http://www.boatsyachtsmarinas.com/bestsellers/html/fuel_cells.html>.
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Propane has not been applied to marine propulsion applications to date. It has a
high octane rating of 112 RON, where a higher compression ratio would result in
improved thermal efficiency. Because propane has a simple chemical composition, more
complete combustion occurs, resulting in lower CO and HC emissions than gasoline.
Propane engines, once fully running (because the propane is already in gaseous form), do
not experience cold-start issues. In terms of durability, propane provides an advantage
over gasoline – engine life could be 50% longer as a result of reduced cylinder wear
during cold starting. There is a penalty of power output from using propane. In order to
compensate for this, the engines size would need to be increased. Gasoline engines can
be converted to run on propane but it would be difficult to optimize. In addition the fuel
tank would need to be enlarged to achieve the equivalent vehicle operating range.128 The
retail price of propane (as of 24 November 2003) was $1.498 per gallon.129
Methanol would provide environmental benefits over gasoline, but modified
engines would not be able to run efficiently on 100% methanol. New technology would
need to be developed and manufactured to obtain maximum performance. Methanol is
similar to ethanol but it has a lower energy content value – 16 MJ/L versus 21.2 MJ/L.
Its wholesale price is between $0.30 and $0.60 per gallon. In addition, increasing the
efficiency of a methanol-burning engine could result in greater NOx emissions. 130
For a detailed discussion of ethanol, refer to the body of the paper.
128 M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994). 129 Weekly Average Propane Prices, 2003, New York State Energy Research and Development Authority, 1 Dec. 2003, <http://www.nyserda.org/nyepf.html>. 130 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000.
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Appendix D. Summary of Material Safety Data Sheets for Gasoline and Ethanol Sources: MFA Oil Material Safety Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm> PC Chem Material Safety Data Sheet, Ethanol <www.chemsupply.com.au/MSDS/1CH9O.pdf> NFPA Safety Ratings
Gasoline Ethanol Health 3 1 Fire 3 3 Reactivity 0 0 Rating descriptions: 1 = slight, 2 = moderate, 3 = high, 4 = extreme Exposure Limits Gasoline Ethanol OSHA 300 ppm 1000 ppm 1 ppm (benzene) Health Effects Gasoline Acute Exposure: Eye: Liquid may cause irritation with erythema and pain. Prolonged or
extensive contact may cause blistering and, in extreme cases epidermal necrolysis. A 12 year old boy partially immersed in a pool of gasoline for 1 hour experienced hypotension, abdominal tenderness, disseminated intravascular coagulation, transient hematuria, nonoliguric renal failure and an elevated serum amylase. Autopsy revealed cerebral edema, diffuse bilateral pneumonia, biventricular cardiac enlargement, toxic nephrosis, fatty infiltration of liver and peripancreatic fat necrosis.
Skin: Repeated or prolonged contact with the liquid may cause irritation,
dermatitis and defatting of the skin with drying and cracking or burns and blistering. Some individuals may develop hypersensitivity, probably due to additives.
Inhalation: At 160-270 ppm throat irritation may occur within several hours. At 2000
ppm mild anesthesia may occur within 30 minutes. Other symptoms of central nervous system depression may include headache, nausea,
Ethanol as Fuel for Recreational Boats Final Report
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vomiting, dizziness, drowsiness, facial flushing, blurred vision, slurred speech, difficulty swallowing, staggering, confusion and euphoria. At higher levels dyspnea, pulmonary edema and bronchopneumonia may develop. Further depression may occur with weak respiration and pulse, nervousness, twitching, irritability, and ataxia. Severe intoxication may result in delirium, unconsciousness, coma, and convulsions with epileptiform seizures. The pupils may be constricted or, in comatose states, fixed and dilated or unequal; nystagmus may also occur. May also affect the liver, kidneys, spleen, brain, myocardium and pancreas. Death may be due to respiratory or circulatory failure or ventricular fibrillation. Extremely high concentration may cause asphyxiation.
Ingestion: May cause irritation and burning of the gastrointestinal tract with nausea,
vomiting and diarrhea. Absorption may cause initial central nervous stimulation followed by depression. Symptoms may include a mild excitation, restlessness, nervousness, irritability, twitching, weakness, blurred vision, headache, dizziness, drowsiness, incoordination, confusion, delirium, unconsciousness, convulsions and coma. Cardiac arrythmias may occur. Transient liver damage is possible. Direct or indirect aspiration may cause chemical pneumonitis with pulmonary edema and hemorrhage, possibly complicated by bacterial pneumonia, and less frequently, by emphysema and pneumonthorax. Signs of pulmonary involvement may include coughing, dyspnea, substernal pain,
Chronic Exposure: Eye: Repeated or prolonged exposure may cause conjunctivitis and possible
gradual, irreversible loss of corneal and conjunctival sensitivity. Skin: Repeated or prolonged contact with the liquid may cause irritation,
dermatitis and defatting of the skin with drying and cracking or burns and blistering. Some individuals may develop hypersensitivity, probably due to additives.
Inhalation: With few exceptions, most of the reported effects of repeated inhalation
are from intentional "sniffing" of gasoline rather than workplace exposure. Reported symptoms include headache, nausea, fatigue, anorexia and weight loss, pallor, dizziness, insomnia, memory loss, nervousness, confusion, muscular weakness and cramps, peripheral neuropathy, polyneuritis, and neurasthenia. It is unclear whether some of these symptoms may have been due to gasoline containing lead. Liver and kidney damage are also possible. In a 90 day study, male but not female rats exhibited a severe, dose-related renal toxicity. In another study, an increase in renal adenomas and carcinomas in male rats and an increase in hepatocellular adenomas and carcinomas in female mice were reported.
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Ingestion: No Data Available Ethanol Acute Exposure: Eye: Liquids may cause stinging and redness, no long term adverse effects.
Vapors may also cause irritation to eyes Skin: May cause mild irritation, Prolonged or repeated contact may cause
defatting of the skin resulting in dermatitis Inhalation: May cause mucous membrane irritation, central nervous system
depression, headache, nausea, and tiredness. Delirium and unconsciousness at high exposure.
Ingestion: May cause vomiting; shallow, rapid pulse; delirium, unconsciousness;
possibly death at VERY high levels. If swallowed, may be aspired resulting in inflammation and possible fluid accumulation in lung.
Chronic Exposure: Liver effects have been observed in oral subchronic and chronic exposures to large amounts of ethanol. Reproductive effects, fetotoxicity, and fetal death observed in some animals.
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Appendix E. Emission Regulations Plots
Figure 9. EPA 2006 Emissions Limits131
Figure 10. CARB 2008 Emissions Limits for Marine Outboards and Personal78
131 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000.
Ethanol as Fuel for Recreational Boats Final Report
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Appendix F. Production of Ethanol132
Ethanol can be manufactured by the fermentation of sugars derived from sugar,
starch, or cellulosic material or by the reaction of ethylene with water. The former is
preferred to produce fuel ethanol, as ethylene is quite expensive.
Ethanol Production from Sugar Crops
Brazil is the world-leader in ethanol production and uses this method. Brazilian
sugar is mostly from sugarcane. Sugar is fermented to ethanol by adding common yeasts,
by the following reaction:
C6H12O6 2C2H5OH + 2CO2
51.1 kg of ethanol can be obtained stoichiometrically for every 100 kg of sugar
fermented, with yeast performed up to 92% of this. The energy balance ratio of ethanol
energy output to fossil fuel input is between 5.9 and 8.2.
Ethanol Production from Starch Crops
The majority of fuel ethanol consumed in the US is made from starch by either
dry or wet milling operations – with the majority of the starch coming from corn. For the
dry milling operation, saccharification occurs by the following hydrolysis reaction:
(C6H10O5)n + nH2O nC6H12O6
Then yeast is added to the sugar and fermented, as discussed above. The resultant “beer”
ethanol is then distilled in a product recovery operation until about 95% purity is reached
– near the azeotropic composition. The mixture is then dehydrated to produce anhydrous
ethanol. Overall, 365 to 390 kg of ethanol can be produced by a metric ton of corn
processed. The wet milling process involves processing the corn in steeping and physical
132 Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished.
Ethanol as Fuel for Recreational Boats Final Report
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milling operations to separate the starch, protein, fiber, and germ. Overall, one metric
tonne of corn can yield 370 kg of ethanol. It is important to note the protein from the
corn and the yeast is sold for animal feed – the major market for which corn is grown.
One volume of ethanol will generate 34% more energy than is need to manufacture it
(overall weighted average of production facilities).
Ethanol Production from Cellulosic Biomass
Ethanol can be produced from sugars contained within the structural portion of
plants. Cellulosic biomass is found in the agricultural residues, forestry residues, and
portions of municipal solid waste. Cellulosic biomass can be grown with low energy
inputs, and can be obtained for minimal cost. Conceptually, the overall process for
converting cellulosic biomass into ethanol is similar to that which processes corn. Acids
and enzymes can be used to convert the cellulose into fermentable sugars. The
simultaneous saccharification and fermentation (SSF) approach is used to convert the
glucose into ethanol as soon as it is formed. Molecular sieves are applied to remove the
remove the water from the azeotropic mixture to obtain anhydrous ethanol. Current
technology results in a net energy output from 16.7 to 21.2 MJ/L of ethanol.
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Figure 11. Schematic for Ethanol Production
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Appendix G. Historical Cost of Ethanol
Figure 12. US Average Ethanol and Corn Prices133
133 Mark Yancy, The Investment Climate for Ethanol Production in California, 2003, BBI, 29 Nov. 2003, <http://www.bbiethanol.com/doe/ca/Yancey-CA-DOE.pdf>.
Ethanol as Fuel for Recreational Boats Final Report
134 Graph of Ethanol Fuel History – 18 Months, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_18-month.html>.
Ethanol as Fuel for Recreational Boats Final Report
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Figure 14. Fuel Ethanol Terminal Market Price (10 Year History)135
135 Graph of Ethanol Fuel History – Last Ten Years, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_10-year.html>.
Ethanol as Fuel for Recreational Boats Final Report
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Appendix H. Ethanol Fuel Calculations Gasoline Equivalent Price Range (Table: Price Range for California Ethanol)
( ))(
223.1$)()(87.0
)(406.1$
gasolinegalgasolinegalEtOHgal
EtOHgal=×
( ))(
366.2$)()(51.1
)(567.1$
gasolinegalgasolinegalEtOHgal
EtOHgal=×
Energy Content Ethanol to Gasoline Ratio
)()(51.1
100,76
000,115
gasolinegalEtOHgal
galBtu
galBtu
=
Optimized Engine Ethanol to Gasoline Ratio
)()(87.0
115100
gasolinegalEtOHgal=
Energy Content Conversion from Gasoline to Ethanol
)(1020.6)()(51.1)(108,770 6 EtOHgal
gasolinegalEtOHgalgasolinegal ×=×
Optimized Engine Conversion from Gasoline to Ethanol
)(1057.3)()(87.0)(108,770 6 EtOHgal
gasolinegalEtOHgalgasolinegal ×=×
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Statewide average for regular gasoline – adjusted for lakeshore consumption from 6/16/03 to 9/15/03136
991.135.022.0861.1 =+− Note: This is a very conservative estimate as we have heard a few quotes about the cost of gasoline in California marinas during the summer of 2003 to be between $2 and $2.50. Not enough responses were received from marinas (as they are now closed) to do a statistical analysis of gasoline selling prices on lakes.
136 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>.
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Appendix O. EDS Results
Figure 21. EDS for Main Jet of Carburetor
Figure 22. EDS for Fuel Pump
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Appendix P. Cold-start Options
The first option is propane. Propane is available in over 10,000 locations
nationwide139, ensuring for reliable availability. Propane tanks are fairly portable, as any
gas grill owner can attest, and can be readily transported. Propane fuel cost $2.09 per
Gasoline Gallon Equivalent as of Feb. 10, 2003, which makes it one of the most
expensive alternative fuels140. The cost of retrofitting a car to run on propane is estimated
to be between $2000 and $2500, but for the cold starting purposes the cost would be
much less141. It is, however, more expensive than a gasoline cold start system due to the
propane torch kit which must be purchased142. The use of propane would be extremely
effective in cold weather, as it has a lower latent heat of vaporization as compared to
gasoline. The harmful emissions from propane are also much less than gasoline, making
it an attractive alternative fuel143. Finally, it is relatively simple to implement a cold start
system, as a control valve would simply need to be opened before starting, and closed
shortly thereafter.
Gasoline is another cold starting option. The obvious benefits of gasoline include
superior availability, easy portability (a one gallon tank is all that is necessary), and a cost
of $1.61 per gallon144. Additionally, the retrofitting cost would be very minor, as the
139 Propane Gas Facts, 2003, The Energy Source Network, 20 Nov. 2003, <http://www.propanegas.com/>. 140 Alternative Fuels Data Center, The Alternative Fuel Price Report (Dept. Of Energy, 3 Mar. 2003), <http://www.afdc.doe.gov/pdfs/afpr_3_3_03.pdf>. 141 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 195. 142 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 143 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 136. 144 Alternative Fuels Data Center, The Alternative Fuel Price Report (Dept. Of Energy, 3 Mar. 2003), <http://www.afdc.doe.gov/pdfs/afpr_3_3_03.pdf>.
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only components necessary are a portable tank, fuel line, pump, and nozzle145. Gasoline
would readily solve the cold start problem, as most automobiles and boats do not have
difficulty starting at cold temperatures while running on gasoline. Extreme cold may
pose starting problems, but again this is not an issue with boats. The environmental
impact of gasoline is the worst of the cold start options, however as the fuel is injected for
just a few seconds, the amount of gasoline combusted is minimal. Finally, the gasoline
system is extremely easy to use, as squeezing the pump once would be sufficient for cold
weather starting.
Natural gas is yet another potential alternative fuel for cold starting use. Unlike
propane, natural gas has a much lesser distribution network, as there are approximately
1300 natural gas refueling sites across the nation146. Since natural gas is stored in high
pressure cylinders, they can be transported to refueling sites. The fuel cost of natural gas
is $1.20 per gasoline gallon equivalent, the cheapest of the alternative fueling options147.
However, the cost of retrofitting is expensive, as a cold start system would need a high
pressure cylinder, high pressure fuel lines, and a pressure regulator to reduce the gas to
atmospheric pressure. Full vehicle conversions range from $2500 - $4000148, and while
the cost for a cold start system would be less, the use of the aforementioned costly
components makes this the most expensive alternative solution. Similar to propane,
natural gas is an effective solution to the cold start problem, with a low latent heat of
vaporization. Natural gas is extremely environmentally friendly, and has the lowest
145 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 146 About Natural Gas, NGV, 19 Nov. 2003, <http://www.ngvc.org/ngv/ngvc.nsf/bytitle/fastfacts.htm>. 147 Alternative Fuels Data Center, The Alternative Fuel Price Report (Dept. Of Energy, 3 Mar. 2003), <http://www.afdc.doe.gov/pdfs/afpr_3_3_03.pdf>. 148 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 194.
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emissions of the alternative fuel options149. However, the natural gas system is not as
simple to use as the propane and gasoline systems, as the valves and controls used to
regulate the high pressure natural gas are somewhat complex.
Hydrogen gas is another potential fuel to solve cold starting issues. Hydrogen can
be transported in tanks or generated from the ethanol fuel. A large problem is the
availability of hydrogen; there is only a handful of hydrogen refueling sites across the
country150. Additionally, as the process of making hydrogen is somewhat expensive, the
cost is prohibitive. Thus, the focus is shifted to using hydrogen which has been internally
generated from the ethanol fuel. This eliminates problems associated with availability
and fuel cost, but generates new problems in other areas. The cost of retrofitting a system
to include a hydrogen reformer is extremely high. While this could potentially be done at
the production stage (at great cost; vehicles with reformers cost significantly more than
those without), to retrofit a gas engine would be extremely difficult, not to mention
incredibly expensive. Also, any hydrogen reformer system would be complicated to
operate for the average recreational boat user. The addition of hydrogen would be an
effective solution to the cold start problem, as hydrogen does not need to be vaporized
and burns easily in cold temperatures151. The environmental benefits of hydrogen are
obvious, as the gas is extremely clean burning152.
149 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 116. 150 Alternative Fuels Data Center, Alternative Fuel Station Counts Listed by State and Fuel Type (Dept. Of Energy 1 Dec. 2003), <http://www.afdc.doe.gov/refuel/state_tot.shtml>. 151 Dr. Gregory W. Davis, Development of Technologies to Improve Cold Start Performance of Ethanol Vehicles, 11 June 2001, Kettering University, 20 Nov. 2003, <http://www.michiganbioenergy.org/pubs/coldstart.pdf>. 152 Energy Efficiency and Renewable Energy, Why Are Hydrogen and Fuel Cells Important, 28 Jan. 2003, U.S. Dept. of Energy, 20 Nov. 2003, <http://www.eere.energy.gov/hydrogenandfuelcells/hydrogen/why.html>.
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Like hydrogen, diethyl ether can be produced from the ethanol itself. There are
no concerns with portability, fuel cost, availability, etc. There are similar problems as
with hydrogen. To convert ethanol into diethyl ether, a catalyst is needed. A modified
catalytic converter, equipped with an alumina based catalyst to convert the ethanol,
would have to be designed and installed. This would likely come at a high cost, if such a
device is even commercially available. Diethyl ether would solve the cold start problem;
the vapor pressure is similar to gasoline. The environmental impact would be similar to
ethanol, however the conversion of ethanol to diethyl ether could potentially create
ethylene, which when converted into ethylene oxide is a toxic emission153.
Another source of diethyl ether is through a cold-starting aid commonly sold in
automotive stores. It is highly portable (as it is sold in a can the size of a spray paint
can), and is affordable at approximately $2. Additionally, the ether is extremely effective
at achieving ignition and preheating the engine, as it is used as a cold starter for gasoline
engines at very cold temperatures. Other benefits include the minimal retrofitting cost
(just buy the can), ease of use (simply requires a short spray into the air intake on the
carburetor, which is easily accessible), and its repeatability as a single canister contains
enough ether for countless starts. The environmental impact of the ether is similar to the
above ethanol-produced diethyl ether.
An electric heater connected to an outlet is one possible option for heating the
ethanol in the carburetor before it is ignited154. Portability is a major problem here, as the
engine must be near an outlet for the heater to operate. While outlets are readily
153 Tomoko Kito and Scott Cowley, Generation of Diethyl Ether in an Ethanol Vehicle System for Cold-Start Assistance, 22 Nov. 1996, Colorado School of Mines, 20 Nov. 2003, <http://www.mines.edu/research/cifer/research/coldstart.html>. 154 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>.
Ethanol as Fuel for Recreational Boats Final Report
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available at marinas, boats kept on moorings and out on the lake would not have access to
these outlets. Thus, if you turned off your engine in the middle of the lake, and the
temperature of the engine dropped, you could be stranded! The cost of the electricity is
minimal, usually free, as most marinas do not charge for use of their electrical outlets.
The retrofit cost would also be minor, as no additional tanks or lines would be needed;
simply an electric heater, placed near or around the carburetor. While this system would
be effective in starting the engine in cold weather, it is not as effective as the alternative
fuel options, due to the time required to heat the ethanol. While the other options
combust immediately, the electric heater would take some time to warm the fuel for
combustion. The environmental impact would be nonexistent, as no additional emissions
or pollutants would result from the electric heater use. Finally this system would only
require plugging a cord into an outlet; far and away the simplest cold start system to use.
The final option is an electric heater powered by a battery. As heaters draw on a
lot of power, this battery would likely be the boat’s battery used to power the onboard
electrical systems. This eliminates the portability problem, as wherever the boat goes, the
battery goes. Availability is not a major concern, as most boats have batteries, however
smaller boats may use an outboard engine but not a battery. Costs are almost identical to
that of outlet electric heaters; however the retrofitting cost may be slightly higher, as
modifications would have to be made to connect an electric heater to a boat battery.
Additionally, there would have to be an easily accessed on/off switch, as disconnecting
the heater from the energy source (the battery) would pose potential electrocution risks,
especially in the presence of water. This system would have the same effectiveness
problem as the other electrical heater – the time to heat the ethanol for combustion.
Ethanol as Fuel for Recreational Boats Final Report
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However, the battery powered heater has another potential problem, in that it draws
electricity from the battery, and could potentially drain the battery. This would be a
major problem, as boat batteries are essential to operation, and relatively costly to
replace155. While the other cold start solutions are very repeatable, as they involve the
use of a fuel, the battery’s potential to be drained makes this option the least repeatable of
the options. Finally, this system would be very easy to operate, as it would involve
turning the heater on and off.
155 Nautical Know How Inc., Marine Battery Primer, 28 Aug. 2000, 20 Nov. 2003, <http://www.boatsafe.com/nauticalknowhow/marine_battery.htm>.
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Appendix Q. Idle Speed Emissions Testing
Unlike the other throttle settings, idle speed is independent of the size of the main
jet. This is due to the diverted fuel flow into the idle jet during idling. To optimize the
carburetor for the fuel, the idle screw allows adjustment until the RPM’s are maximized.
For gasoline, this constitutes a 3.5 turn counterclockwise from tightened position. After
experimentation using a tachometer to measure RPM’s, the ideal setting for ethanol was
determined to be 1 turn counterclockwise. The emissions for gasoline and ethanol in
their respective ideal idle screw settings are presented in the following graphs.
Hydrocarbon and NOx Emissions
803.8
164.5
0100200300400500600700800900
Gas EtOH
Fuel
PPM Idle Throttle
Figure 23. Hydrocarbon and NOx Emissions
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Figure 24. CO and CO2 Emissions
For both sets of emissions, there is a dramatic improvement associated with the
use of ethanol over gasoline. Total hydrocarbons and NOx are greatly reduced, as is the
CO%. CO2% increases considerably, representing an increased efficiency associated
with ethanol operation. This is due to the fine-tuning of the idle screw setting, which is
impossible during operation in the other throttle ranges, explaining their lower CO2
values.
CO and CO2 Emissions
0.00%2.00%4.00%6.00%8.00%
10.00%12.00%14.00%16.00%
Gas EtOHFuel
% Idle Throttle CO%Idle Throttle CO2%
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Appendix R. Tohatsu Power Curve
Figure 25. Power curve for Tohatsu 5 hp four-stroke outboard engine156
156 Garland Lewis, Tohatsu, “FW: Tohatsu,” email to author, 27 Feb 2004.
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Appendix S. Mid-throttle Power Testing
A thermodynamic analysis of the cooling water was used to estimate the power at
mid-throttle. The outboard engine was water-cooled: water from the bucket was sucked
up, heated by the engine and discharged into a different bucket. The engine initially ran
for twelve minutes to allow it to warm up. Thermometers were used to determine the
temperature of the “cold” and “hot” cooling water. The hot discharged water filled a
beaker for 10 seconds and then the volume was measured. From this data, the volumetric
flow rate could be obtained. This procedure was repeated for the gasoline engine and for
the four different main jet sizes for ethanol.
The thermodynamic analysis of the water temperature change made the
assumption that the power of the engine caused the heat rate that raised the temperature
of the water. The following equation was used to calculate the power:
TcQP p∆= ρ)80.0( Eq. 3
where is the power in kW, Q is the volumetric flow rate in m3/s, ρ is the density of
water (998 kg/m3), cp is the specific heat of water at constant pressure (4.2 kJ/kg-
K),157 and ∆T is the temperature change in K
The value was multiplied by 0.80 to attempt to account for energy lost in this conversion
to bodies other than the water. The power was subsequently converted into hp.
157 Michael Moran and Howard Shapiro, Fundamentals of Engineering 4th Ed. (New York: Wiley, 2000).
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