1 Energy and Environment Environmental Impacts of Renewable Energy-Part II Dr. Hassan Arafat Department of Chem. Eng. An-Najah University (these slides.
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Energy and Environment
Environmental Impacts of Renewable Energy-Part II
Dr. Hassan ArafatDepartment of Chem. Eng.
An-Najah University
(these slides were adopted, with modification, from Ms. Paulina Bohdanowicz , KTH Institute, Sweden)
Biofuels as
energy source
• CO2-neutral – photosynthesis:
{CH2O} + O2 => CO2 + H2O
Combustion:{CH2O} + O2 =>
CO2 + H2O + energy
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Wood, energy crops, waste,
dung etc.
Micro-algae and
oilseed crops
Alcohol fuels
Biogas
Syngas
Gasoline
Bio-diesel
Biological conv.
Direct combustion
Thermal conv.
Chemical conv.
Motor vehicles,
H2 fuel for fuel cell
Cooking
Heating
Steam generation
Electricity generation
H2 fuel for fuel cell
Motor vehicles
Motor vehicles
Pathways for production of biofuels
Potential causes of concern associated with biomass/biofuels
• LAND– Land use conflict - fertile land is used based on
cash oriented use, cash crops for export or food production. Pressure on farmers to cut down forest and cultivate virgin soil
– Deforestation - local wood extraction exceeds local production also due to land clearance
– Desertification - when forest are cut down and the surface of the ground is exposed. Evapotranspiration increases and the soil dries
– Erosion - gradual wearing away of land by water and wind
– Visual impact– Reduction in biological diversity– Typically high input of energy required (fertilisers,
harvesting processing)Source: Boyle et al. 2003; Baguant J., Life Cycle Assessment of Sugar Cane Bioenergy Systems for Electricity Production, PROSI Magazine – Jan. 1998 – No. 348 – Research, online paper available at
http://www.prosi.net/mag98/348jan/energ348.htm
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Clearance
Cut downTypical
native
Chilean forest
Desertification : more surface exposed. Evapotranspiration
New plantation
Even worst: a cheaper way
No need to cut down the trees, No transportation needed,
Less man power.
Burning of virgin forest.
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Potential causes of concern associated with biomass/biofuels
• New agricultural land, less retention of water in soil, desertification (higher evapotranspiration)
• Use of scarce water • Improper irrigation of energy crops => soil
salinity • Ground water pollution due to fertilisers• H2O for biogas production and distilleries =>
production of waste water rich in N2, phosphorous and potassium. These nutrients stimulate the growth of plant – eutrophication (depletion of O2 in lakes and rivers)
Source: Boyle et al. 2003; Baguant 1998
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Potential causes of concern associated with biomass/biofuels
• Local effects - indoor pollution (biomass for heating)
• Regional effects - the main pollutants, SO2 and NOx. Soil and water acidification, damage to fish population, degradation of plants, effects on human respiratory function.
• Global effects: emissions of GHG– sugar cane bio-energy systems like the bagasse to
electricity fuel chain are in fact net emitters of CO2 – but compared to coal used for power generation,
the avoided CO2 (i.e. not emitted to the atmosphere) with sugar cane biomass can vary between 0.96 kg CO2/kWh and 1.10 kg/kWh
Source: Boyle et al. 2003; Baguant 1998
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Potential causes of concern associated with biomass/biofuels
Most of biofuels in developing countries are used in households, having a more direct impact.
• Respiratory infections• Chronic obstrction lung diseases• Low birth
weights• Cancer• Eye
problems0
10
20
30
40
50
60
70
Exposure(GEE)*
Ruralindoor
Ruraloutdoor
Urbanindoor
Urbanoutdoor
GEE is the Global exposure equivalent, based on the pollutants concentration and the hours of exposed to the pollutant
Particulate Exposures in Developing CountriesParticulate Exposures in Developing Countries
Source: Boyle et al. 2003; Baguant 1998
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Only production and combustion of biofules on a sustainable
basis is CO2-neutral
Positive impacts of biofuels as energy source
• Reduction of greenhouse gas (GHG) emissions along with odor by landfill gas extraction for bioenergy
• Reduction of NOx emissions
• Reduction of sulphur oxides emissions – using biomass for 5% of a coal-fired power
plant’s heat input would reduce SO2 emissions by aprrox. 5%
• Avoided emissions & landfill requirements by municipal solid waste combustion (MSWC) technology
Source: EREN, Renewable Electricity from Plant Material,
BIOPOWER, Department of Energy, 2002
Positive impacts of biofuels
as energy source• Provision of clean gas (biogas) for cooking,
heating etc. • Biomass energy crops can improve water
& soil quality and also improve biodiversity• Some energy crops can be used
for the treatment of wastewater• Reduction of water pollution by animal
waste, fertilisers and pesticides• Job creation/rural development
Source: EREN, Renewable Electricity from Plant Material,
BIOPOWER, Department of Energy, 2002
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Positive impacts of biofuels as energy source
• According to EPA estimation, cars burning pure methanol & ethanol can reduce VOC emissions from the tailpipe by 85 to 95%, while CO emissions by 30 to 90%
• Both methanol & ethanol are likely to be key hydrogen fuels for fuel cells.
Cumulative CO2 benefits of ethanol compared to RFG in 2010 (NREL)
Bioenergy Information Network (BIN), A gateway to information about fast growing trees, grasses and residues for fuels and power, online
publications, last updated 08.02.02 available at http://bioenergy.ornl.gov/doeofd/biowin/stratgy.html
GHG emission intensities for selected fuels,
g CO2/kWh electric
Source: Boyle et al. 2003
Conventional coal
960-1300 Biomass 37-166
Advanced coal
800-850 Photovoltaic 30-150
Oil 690-870 Hydroelectric 2-410
Gas 460-1230 (220 CHP)
Wind 11-75
Nuclear 9-100
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Costs of electricity with and without external costs
Electricity Source Generating Costs1 External Costs2 Total Costs
(cents per kilowatt-hour)
Coal/lignite 4.3–4.8 2–15 6.3–19.8
Natural gas (new) 3.4–5.0 1–4 4.4–9.0
Nuclear 10–14 0.2–0.7 10.2–14.7
Biomass 7–9 1–3 8–12
Hydropower 2.4–7.7 0–1 2.4–8.7
Photovoltaics 25–50 0.6 25.6–50.6
Wind 4–6 0.05–0.25 4.05–6.25
1For the United States and Europe.2Environmental and health costs for 15 countries in Europe.Source: Worldwatch Institute, State of the world 2003.
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Energy & Employment
Germany: wind energy has a share of around 5 % of electricity generation and employs ~ 100,000 people, whereas nuclear power supplies 30 % of the electricity and employs only 38,000 people [Jochen Twele, Windenergie – Technik & Repowering, BWE, Berlin 2002.]
Source: Jochen Twele, Windenergie – Technik & Repowering, BWE, Berlin 2002
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Other major environmental problems
• Water• Waste• Chemicals• Consumerism…
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Water availability, in 1000 m3/inhabitant/year
Source: UNEP, 2002
Very low –
1 to 2,
Medium – > 5 to 10, High – > 10 to 20, Very high – > 20
Catastrophically low– < 1,
> 2 to 5, Low –
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Selected water
stressed countries
Effluent from water desalination plant, Kuwait
Source: WCD 2000
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Water pollution
Effluent from water desalination plant, Kuwait
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Consumerism
• How much does one own?• How much of the things one has – one
does not need• How much of the things one actually
needs – one cannot find
September 12, 2001, vice president Cheyenne:
“If you are patriotic – go and buy something American”
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Waste generation/disposal
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Coal Oil Gas Wood Nuclear Solar PV
Ash FGD waste Gas sweetening waste Radioactive waste Toxic waste
million tonnes / GWeWaste generated annually in fuel preparation and plant operation
• History• Current
status• Mechanism
• Impacts • Mitigation
– No disposal of power plant waste law
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Waste generation/disposal
Source: EEA 2003
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Waste generation/disposal
Source: EEA 2003
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Waste generation/disposal
Waste dump, Mexico
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Soil degradation
Source: EEA 2003
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Conclusion
• All energy sources and methods of conversion have environmental impacts
• Fossil fuels have the highest impacts, but RETs are not environmentally neutral either
• Nevertheless if externalities were included in energy costs – RETs would prove to be cheaper than conventional sources
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Conclusion
• …and in order to achieve long term sustainability of human civilisation a shift to renewables is necessary
• Additionally, most of the renewables are available in developing countries and could be used to allow ”leap frogging” development of these countires (instead of transferring dirty technologies of industrialized world)
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