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AP Environmental Science

Mr. GrantLesson 96

Alternatives to Fossil Fuels

&

Nuclear Power

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Objectives:• Define the terms nuclear fission and nuclear fusion.• Discuss the reasons for seeking alternatives to fossil fuels• Summarize the contributions to world energy supplies of

conventional alternatives to fossil fuels• Describe nuclear energy and how it is harnessed• Outline the societal debate over nuclear power• TED - Physicist Steven Cowley is certain that nuclear fusion

is the only truly sustainable solution to the fuel crisis. He explains why fusion will work -- and details the projects that he and many others have devoted their lives to, working against the clock to create a new source of energy.

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Define the terms nuclear fission and nuclear fusion.

Nuclear Fission

Nuclear Fusion

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Discuss the reasons for seeking alternatives to fossil fuels.

• Fossil fuels are nonrenewable resources and we are gradually depleting them.

• Fossil fuel combustion causes air pollution that results in…− Environmental and health impacts.− Contributes to global climate change.

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Alternatives to Fossil Fuels

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Summarize the contributions to world energy supplies of conventional alternatives to fossil fuels.

• Biomass provides 10% of global primary energy use...- Nuclear power provides 6.3%- Hydropower provides 2.2%

• Nuclear power generates 15.2% of the world’s electricity…− Hydropower generates 16.0%

• “Conventional energy alternatives” are the alternatives to fossil fuels that are most widely used...− Biomass energy− Nuclear energy− Hydroelectric power

• “Conventional energy alternatives” in terms of renewability and environmental impact fall between fossil fuels and less widely used “new renewable” sources.

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Conventional alternatives

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Conventional alternatives

provide energy

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The U.S. relies on fossil fuels

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Describe nuclear energy and how it is harnessed.

• Nuclear power comes from converting the energy of subatomic bonds into thermal energy, using uranium isotopes.

• Uranium is mined, enriched, processed into pellets and fuel rods, and used in nuclear reactors.

• By controlling the reaction rate of nuclear fission, nuclear power plant engineers produce heat that powers electricity generation.

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Nuclear Power

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Fission releases nuclear energy

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Nuclear energy comes from uranium

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A typical light water reactor: fission in reactors generates electricity

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Breeder reactors

make better use of fuel

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Fusion remains a dream

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Outline the societal debate over nuclear power.

• Advocates of “clean” energy support nuclear power because it lacks the pollutant emissions of fossil fuels.

• For many people, the risk of a major nuclear power plant accident (like Chenobyl), outweighs the benefits of clean energy.

• The disposal of nuclear waste remains a major dilemma…- Temporary storage and single-repository plans each involve

health, security, and environmental risks.

• Economic factors and costs overruns have slowed the nuclear industry’s growth.

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Nuclear power

delivers energy cleanly

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Coal versus nuclear power

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Coal versus nuclear power

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Nuclear power poses small risks

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Meltdown at Three Mile Island

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Chernobyl was the worst

accident yet

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The Chernobyl accidentThe destroyed reactor was encased in a massive concrete sarcophagus to contain further leakage

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Atmospheric currents carried radioactive fallout from Chernobyl across much of the Northern Hemisphere

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The Fukushima Accident

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Smaller-scale accidents have occurred

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Waste disposal remains a problem

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Spent fuel rods must be stored

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U.S. power plants store tons of waste

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Waste storage at Yucca Mountain, Nevada

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Yucca Mountain, Nevada

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Concerns with Yucca Mountain as a site

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Dilemmas have slowed nuclear power’s growth

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The future of U.S. nuclear energy