The Sustainable Energy Challenge

The Sustainable Energy Challenge

Lecture Series in Sustainability

Science

by

Toni Menninger MSc

http://www.slideshare.net/amenning/ [email protected]

The Sustainable Energy Challenge

The Sustainable Energy Challenge

1. The Age of Fossil Fuels

2. Energy use in global perspective

3. The Sustainable Energy Challenge

4. Review: The Laws of Energy

• The Law of Energy Conservation

• Energy Transformations

• The Second Law

• Heat Engines

• Conversion efficiency

• Energy Return on Investment (EROI)

The Sustainable Energy Challenge

5. Energy Efficiency potentials

• Systemic approaches

• Individual approaches

6. Economic Considerations

• External Costs of Energy

• Energy Taxes

• Energy Subsidies

7. Power sources

• External Costs of Energy

• Energy Taxes

• Energy Subsidies

8. Conclusion: Does “Clean Energy” Exist?

The Sustainable Energy Challenge

Oil rig explosion in Gulf of Mexico, April 20, 2010

The Sustainable Energy Challenge

Mountaintop removal coal mining in West Virginia, 2003

The Sustainable Energy Challenge

Fukushima nuclear disaster, March 2011

The Sustainable Energy Challenge

The Sustainable Energy Challenge

The Sustainable Energy Challenge

Fossil fuel combustion is the main cause of climate change and a main cause of air and water pollution and acid rain Mining and extraction of fossil fuels is ecologically and socially destructive: e. g. mountain top coal mining in the Appalachians, oil spills, coal mine accidents, oil rig explosions, social unrest (e. g. Nigeria), geopolitical instability (Iraq, Iran, Central Asia etc.), petro dictatorships in the Middle East... Fossil fuels are nonrenewable resources and their continued use is not sustainable. The Fossil Fuel Paradox: There is too much and not enough of it… More than enough to destabilize the climate system but not enough to preserve our current oil-dependent lifestyle much longer

The Age of Fossil Fuels

Worldwide oil production is expected to peak in the near

future. Although coal is still relatively abundant and

“nonconventional” oil sources may increasingly be

exploited, the era of “cheap oil” is probably over.

Industrial civilization

has been enabled by

a “fossil fuel subsidy”

- sunlight

concentrated and

stored in deposits of

hydrocarbons that

are relatively easily

accessible, easy to

transport, store, and

use.

The Age of Fossil Fuels

Oil discovery rate is declining (Hall and Day, American

Scientist 2009)

Peak Oil ?

Energy return

on investment

(EROI, EROEI)

is declining

(Hall and Day,

American

Scientist 2009

– required reading)

Petroleum Consumption by the numbers

• Global supply 2010: 88 million barrels a day , or 32 billion barrels a year

• Total US demand : 19 million barrels a day, or 7 billion barrels a year

• The USGS estimates 5 – 16 billion barrels recoverable in the Arctic National Wildlife Refuge (ANWR) How long does that last?

Source: Tom Murphy

Can we replace fossil fuels with renewables?

The Sustainable Energy Challenge

The Sustainable Energy Challenge

Can we meet the global energy need at US consumption level?

Source: Tom Murphy

Energy use in global perspective

http://en.wikipedia.org/wiki/List_of_countries_by_energy_consumption_per_capita

Google public data explorer

Total energy consumption per capita by US state

Energy use in global perspective

Google public data explorer

Industrial civilization is based on fossil fuel energy

Primary energy use in more and in less developed countries

Tropical deforestation accounted for 10 percent of global carbon dioxide emissions between 2000-2005 — a substantially smaller proportion than previously estimated — argues a new study published in Science. Read more at http://news.mongabay.com/2012/0621-carbon-emissions-from-deforestation.html#7lxeme2XSOxrLXg0.99

Gross annual carbon emissions resulting from gross forest cover loss and peat drainage and burning between 2000 and 2006 in Giga Tons Carbon per year

Global Warming: what to do?

● Reduce greenhouse gas emissions (reduce fossil

fuel use, stop deforestation)

● Enhance natural carbon absorption by soil and

vegetation (reforestation, forest management,

conservation tillage, biofuels from algae)

● Technically remove greenhouse gases from the

atmosphere (“carbon sequestration”, “carbon

capture and storage”)

● Try to counteract warming trend with artificial

cooling (“geo-engineering”)

● Do nothing, hope for the best, try to adapt

(“business as usual” (BAU))

“Stabilization wedges” proposed by Pacala and

Socolow (Science, 2004)

“Stabilization wedges” proposed by

Pacala and Socolow (Science, 2004)

● Wedges 1-4: Energy efficiency and conservation

● Wedge 5: Fuel shift from coal to gas

● Wedges 6-8: Carbon capture and storage (CCS)

● Wedge 9: Nuclear fission

● Wedges 10-13: Renewable energy

● Wedges 14-15: Forests and agricultural soils

Key to a sustainable energy

future: large improvements in

energy conservation and the

transition to a “low-carbon”

energy economy.

The Sustainable Energy Challenge

The Sustainable Energy Challenge What is “clean”/ ”sustainable” energy? How do we define + measure “energy sustainability”?

Sustainable energy considerations • Energy efficiency

• Availability, intermittency

• Transport, storage

• Environmental impact (pollution, biodiversity)

• CO2 Emissions (based on Life Cycle Analysis)

• Land use intensity

• Material resource requirements

• Energy return on energy investment (EROI)

• Economic cost

• Social acceptance

• … … …

Sustainable energy considerations: Carbon emissions

• Natural gas (methane) emits less pollution and less CO2 per unit of energy compared to coal.

• But it is a potent greenhouse gas. Methane leakage might cause more harm than is avoided through fuel shift.

Sustainable energy considerations: Carbon emissions • Nuclear, wind, solar and hydro power generation

do not emit CO2 during operation but indirect emissions from the life cycle must be taken into account. Results are contentious.

World Nuclear Association Oxford Research Group

Land use intensity of selected power sources

“Energy Sprawl or Energy Efficiency”, McDonald et al., PLOS One 2009

Review: The Laws of Energy • Energy is a physical entity that can be

measured and quantified.

• Energy (Work) is defined as a force (measured in N [Newton]) acting through a distance and measured in J [Joule]: 1J=1Nm

• Power is a measure of energy flow over time, measured in W [Watt]: 1 W= 1J/s

Required reading: Energy Literacy

Review: The Laws of Energy • A vehicle must expend mechanical energy

to overcome the forces of friction and air resistance.

• To climb stairs, you have to expend energy to overcome the gravitational force. The amount of gravitational energy is proportional to the weight of the body and the vertical height traveled.

• Hydropower generation is proportional to the height of the dam and the mass of the water running through turbines.

Review: The Laws of Energy Different kinds of energy have been measured in different units (Btu, kWh, kcal) but they can all be converted into each other.

• Mechanical energy (work)

• Heat (Thermal) energy

• Kinetic energy

• Gravitational energy

• Radiation

• Chemical energy

• Electric energy

Review: The Laws of Energy (The Laws of Thermodynamics) First Law (Law of energy conservation): Energy can be neither created nor destroyed, only transformed. The conversion efficiency is the percentage of “useful” energy

efficiency= 𝑜𝑢𝑡𝑝𝑢𝑡 𝑒𝑛𝑒𝑟𝑔𝑦

𝑖𝑛𝑝𝑢𝑡 𝑒𝑛𝑒𝑟𝑔𝑦 x 100

Review: Energy transformations

Review: The Laws of Energy Second Law of Thermodynamics (Law of entropy): • Heat energy flows spontaneously from higher to

lower temperature but not the other way.

• Heat cannot be completely converted to mechanical energy. The conversion efficiency of a heat engine cannot exceed the Carnot efficiency (1 − 𝑇𝐶/𝑇𝐻), the rest is lost as waste heat.

• The entropy (“disorderliness”) of a closed system can only increase. High-grade (useful) energy is dispersed into low-grade (waste) energy. Decreasing entropy requires importing energy.

Review: Heat engines

The energy conversion process from heat

to mechanical energy taking place in a heat

engine necessarily involves a loss of waste

heat. Carnot's law states that the maximum

conversion efficiency ( )that a heat engine

can achieve depends on the difference

between the absolute temperatures of the

hot (TH) and the cold (TC) reservoir :

Absolute temperature is

measured in Kelvin.

Tabs=Tcelsius+273.15

Implication of the Second Law

Heat engines (combustion motor and thermal

power plant) are inherently inefficient! A large

part of the heat energy is lost, unless it can be

made useful for heating (CHP – Combined Heat

and Power)

TH typically 350-550 ºC, about 600-800 K; TC about 25 ºC or

300 K. Optimal efficiency 50-60%, actual efficiency 15-40%.

Process Energy efficiency Theoretical limit

Photosynthesis Up to 6%

Muscle 15% - 25%

Internal combustion engine 15% - 20% 55% (Carnot efficiency)

Electric car up to 80%

Thermal power plant 30% - 40% global average 32%

≈60% (Carnot efficiency, depends on temp.)

Cogeneration (CHP) Up to 90%

Hydropower plant 80% - 95%

Wind turbine 15% - 35% 59%

Photovoltaic cells 10% - 15% 35% (with caveats)

Solar water heater 50% - 75%

Electric heater 100%

Gas or wood heating (modern) 75% - 95%

Heat Pump COP (Coefficient of Performance) > 1 SEER (Seasonal Energy Efficiency Ratio)

Conversion efficiency

Energy return

on investment

(EROI, EROEI)

is declining

(Hall and Day,

American

Scientist 2009

– required reading)

EROI corn ethanol 1.3:1

http://ngm.nationalgeographic.com/2007/10/biofuels/biofuels-interactive

EROI - Energy Return on Investment

• The Energy Return on Investment

(EROI/EROEI) is the energy cost of

acquiring an energy resource. It is not the

same as Energy Efficiency.

• EROI is the ratio of the amount of usable energy

acquired from a particular energy resource to the

amount of energy expended to obtain that energy

resource. Example: EROI = 4 means that each unit of

energy invested yields 4 units of output. Conversely, net

energy output is 75% of gross energy output.

• An “energy resource” with an EROI < 1 is a net sink of

energy.

Energy Efficiency potentials: systemic

approaches

● Co-generation (Combined Heat and Power, CHP

Energy Efficiency potentials: systemic

approaches

● Co-generation

(Combined Heat and

Power, CHP)

● “Smart Grid”: smooth out

demand curve by giving

incentives to consumers,

efficiently controlling energy

flow during peak demand.

Reducing peak demand will

significantly improve overall

efficiency

http://www.oe.energy.gov/S

martGridIntroduction.htm

Energy Efficiency potentials: systemic

approaches

● Co-generation (Combined

Heat and Power, CHP)

● “Smart Grid”

● Transportation efficiency:

Urban design to favor walkable,

bikable neighborhoods, efficient

mass transit, smaller cars, car-

sharing, hybrid technology,

replace short distance air travel

by rail, efficient use of air travel

capacity, move freight transport

from truck to barge and rail

UACDC: Visioning Rail Transit in NWA

Energy Efficiency potentials: individual

approaches

Energy Efficiency potentials: individual

approaches

● Building efficiency: building size, air-tightness, insulation, low-E

windows, heat-recovery ventilation, passive solar design, reflective

roof, efficient wood heating, geothermal heat pumps, solar water

heating, roof PV cells, zero-energy buildings

● Most contractors oversize air conditioners and undersize air

supply (at least 2 sqft per ton recommended)

● Appliances (inefficient: top-loader washer, oversized French

door refrigerator with in-door ice dispenser)

● Lighting: efficient light bulbs, natural light and movement

sensors in office + retail buildings

● Electronic devices: improved power control for computers,

monitors, printers, TVs, even small devices like cell-phone

chargers etc. can save energy; stand-by mode (“vampire energy

loss”) is a huge energy drain

Energy Efficiency: economic

considerations

● Investment in energy efficiency and conservation pays off

● “Conservation is the quickest, cheapest, most practical source

of energy”- Jimmy Carter, 1977

Then why is there so little progress in energy efficiency?

● Up to recently, energy prices have been historically cheap,

especially in North America.

● Economic incentives are effective. Businesses and consumers

respond to increasing energy cost (e. g. increased US demand for

transit, increased interest in home energy improvements)

● Energy policy should be consistent and predictable

● Energy or pollution taxes or similar mechanisms (e. g. cap and

trade) provide consistent economic incentives for conservation.

Case study: “Progress” in automobile

efficiency

“Jevons’ Paradox”

Technological progress that increases the efficiency with which a resource is used tends to increase (rather than decrease) the rate of consumption of that resource => Absent economic incentives, technology will not by itself promote conservation!

Economic incentives are effective! Prices change behavior

Oil price

Economic incentives are effective! Prices change behavior

High fuel taxes promote fuel conservation

Energy Efficiency: economic considerations

● Energy taxes are not a “drain” on the economy – they move

resources from less to more energy efficient sectors.

● Revenues from energy taxes flow back into the domestic economy

– money spent importing energy is lost from the domestic economy.

● Revenues from energy taxes can be redistributed to soften the

impact on low-income groups, or used to create jobs, or invested in

energy efficient infrastructure.

● Energy generation and use causes massive negative externalities

(carbon emissions etc.). Taxes designed to compensate for a

negative economic externality are known as Pigouvian taxes.

Standard economic theory predicts that Pigouvian taxes increase

economic efficiency.

● Difficulty: quantifying the externality

● Difficulty: energy intensive industries will go where energy taxes and

regulations are least strict

Economic

considerations:

External costs

of Energy

Hidden Costs of Energy: Unpriced Consequences of

Energy Production and Use

A report by the National Research Council’s Committee on Health,

Environmental, and Other External Costs and Benefits of Energy Production

and Consumption

Freely available at http://www.nap.edu/catalog.php?record_id=12794

Economic considerations: energy taxes

“Environmental taxes can play a central role in reducing the fiscal gap in the years to come. These are efficient taxes because they tax “bads” rather than “goods.” Environmental taxes have the unique feature of raising revenues, increasing economic efficiency, and improving the public health. (…) It is striking how the political dialogue in the US has ignored a policy that has so many desirable features. (…) Simply put, externality taxes are the best fiscal instrument to employ at this time, in this country, and given the fiscal constraints faced by the US.”

Economist William D. Nordhaus

Energy Subsidies: “Black not Green”

NYT, July 3, 2010: “oil production is among the most heavily subsidized businesses”

Power sources – a brief overview

Coal

● Relatively abundant & cheap

● Biggest source of carbon emissions

● Emits many pollutants incl. Mercury, sulfur

● Coal mining often environmentally destructive –

Mountaintop removal in Appalachia

● Carbon Capture and Storage (CCS) technically

feasible method of minimizing carbon emissions

but expensive and energy intensive

Power sources – a brief overview

Natural Gas

● Less pollution, 40% less carbon emitted per unit

of energy, potential as transportation fuel

● Problem of Methane leakage

● “Hydrofracking”, a relatively recent drilling

technique, is controversial because of the

use of toxic chemicals, high

freshwater use, potential for

watershed contamination,

disposal of large amounts of

fracking fluid, injection wells

causing small earthquakes …

Power sources – a brief overview

Nuclear fission power

● Uranium relatively abundant but not unlimited

● Low GHG emissions during operation, GHG emissions during

construction and mining

● Uranium mining very “dirty”, huge environmental impact

● Socially contentious technology

● Investment cost of building new plants relatively high, protracted

permit and construction process, huge delays and cost overruns

universally observed

● Most existing plants are decades old, amortized and highly

profitable but often fail to comply with modern safety standards.

Operators tend to resist costly upgrades, have big economic

incentives to continue operating unsafe plants. Whose interests

do regulators protect?

Power sources – a brief overview

Nuclear fission power

● Safety issues: Fukushima, Chernobyl, Three Mile Island only tip

of the iceberg; there is a long list of incidents involving nuclear

power plants. Incidents often lead to prolonged, expensive

interruption of operation.

● Radioactive Tritium leaked from Yankee power plant in Vermont,

2010 (http://healthvermont.gov/enviro/rad/yankee/tritium.aspx)

● Release of 18,000 liters of solution containing Uranium at

Tricastin, France, in 2008

● Nuclear power plants potential terrorist targets

● Nuclear proliferation concerns

● Waste disposal and decommissioning difficult if not unfeasible,

costs generally not priced into electricity

Power sources – a brief overview

Nuclear fission power

Tchernobyl: more than 20 years after

the disaster, the number of fatalities is

still disputed. The lowest estimate – 56

direct deaths and 4000 long term

cancer victims – was published by the

IAEA, an organization constitutionally

charged with promoting nuclear energy.

Anti-nuclear groups estimate 50,000

potential fatal cancer incidents.

Hundreds of thousands of workers

(“liquidators”) came close to the reactor

core during clean-up work.

● Selection of sites to look up on wikipedia: Sellafield, Mülheim-

Kärlich_Nuclear_Power_Plant, Schacht_Asse_II,

Tricastin_Nuclear_Power_Center, Olkiluoto_Nuclear_Power_Plant, Dounreay

http://www.monbiot.com/archives/2006/09/12/a-catalogue-of-idiocy/

Power sources – a brief overview

Power sources – a brief overview

Wind

● Large wind farms economically competitive

● No fuel required, no GHG emissions during operation

● Low maintenance cost, but large upfront investment

● GHG emissions during construction

● Potential for ecological disruption, impact on birds and

bats uncertain, high land use intensity per Megawatt

(“Energy Sprawl or Energy Efficiency”, PLOS One 2009),

● Power output proportional to square of diameter and third

power of wind velocity, transformation efficiency up to 35%

(small scale turbines less efficient), intermittency and

fluctuation of wind direction and velocity reduces efficiency

further.

Power sources – a brief overview

Wind

● Small and intermediate wind

power units valuable for off-the

grid, remote areas, developing

countries but not a significant

contribution to energy needs of

developed countries.

Power sources – a brief overview

Hydro power

● Very high conversion efficiency

● No pollution or GHG from operation

● Reservoirs can be used as energy storage

● Potential ecological disruption by large as well as small

dams

● Loss of valuable farmland or wildlife habitat

● Large numbers of people relocated because of large dam

projects

● Power disruption during drought

● Other issues with dams

Power sources – a brief overview

Biofuels

● Potentially renewable, low-GHG energy source, potential

alternative transportation fuel

● Many issues:

- Land-use intensity

- Water intensity

- Energy inefficiency: very low EROI in some cases

- Competition with food production

- Deforestation for palm oil plantations in Tropics

● Different kinds of biofuels from different sources (e. g. algae,

cellulosic biomass, recycled vegetable oil, sugar cane, corn):

sustainability assessment different in each case

● Currently no plausible, sustainable large-scale source of

biofuels

Recommended readings: NGM; Thermodynamics of the Corn-Ethanol Biofuel Cycle;

“Hunger Games”; Bioenergy – Chances and Limits

Power sources – a brief overview

Solar Power

● Ideal, abundant, pollution free source of power

● Photovoltaics still expensive, manufacturing requires rare

materials

● Maximum production during day time, when demand is highest

● Problems of predictability, reliability, storage

● Land use intensity less than wind but more than coal

● Solar water heating very efficient and cheap, mandatory in

many Mediterranean countries, underused in US (why?)

● Many uses on many scales, including low-tech applications

relevant to developing countries, off the grid use

● Immense potential, few draw-backs

Power sources: Solar Power

The land area needed to produce 18 TW of electricity using 8% efficient photovoltaics, shown as black dots. Source: WikiMedia, Do the Math

Germany has promoted

the installation of PV

panels with subsidies.

Good policy?

Power sources – a brief overview

Conclusion: does “Clean

Energy” exist?

How would you implement a

national (global?) energy policy

promoting sustainability?

This presentation is part of the Lecture Series in Sustainability

Science. © 4/2014 by Toni Menninger MSc. Use of this material for

educational purposes with attribution permitted. Questions or

comments please email [email protected].

Related lectures and problem sets available at

http://www.slideshare.net/amenning/presentations/:

• Growth in a Finite World: Sustainability and the Exponential Function

• The Human Population Challenge

• World Hunger and Food Security

• Economics and Ecology

• Exponential Growth, Doubling Time, and the Rule of 70

• Case Studies and Practice Problems for Sustainability Education:

• Agricultural Productivity, Food Security, and Biofuels

• Growth and Sustainability

… and more to come!

The Sustainable Energy Challenge