Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings 20 Conventional Energy Alternatives Part B PowerPoint ® Slides prepared by Jay Withgott and Kristy Manning Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Nuclear waste disposal Nuclear waste must be disposed where it will not escape.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nuclear waste disposal Nuclear waste is stored at 125 sites in 39 states.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nuclear waste disposal At Yucca Mountain, all nuclear waste in the U.S. would be buried in a network of tunnels deep underground.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Health impacts of nuclear accidents The incidence of thyroid cancer jumped in regions around Chernobyl starting 4 years after the accident.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Greenhouse gas emissions Coal, oil, and natural gas emit far more greenhouse gases than do renewable energy sources and nuclear energy.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Viewpoints: Nuclear power Karl Grossman John Ritch “We need not take the colossal risk of atomic power. Safe, clean, sustainable technologies are here today and can unhook us from fossil fuels: wind, solar, geothermal, and hydrogen power, among others.” “With carbon emissions threatening human health and the stability of the biosphere, the security of our world requires a massive transformation to clean energy…Renewables such as solar, wind, and biomass can help. But only nuclear power offers clean energy on a massive scale.”

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Biomass Organic substances produced by recent photosynthesis (unlike fossil fuels, products of ancient photosynthesis)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Uses of biomass energy More than 1 billion people burn fuelwood or charcoal as their principal power source for cooking, heating, etc. New uses: Burning in power plants to produce biopower Converting into biofuels to power automobiles Many new biomass resources are the waste products of preexisting industries or processes, e.g., forestry, landfill waste.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Biomass energy consumption Energy consumption patterns vary greatly between developing and developed nations.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Biofuels Ethanol = alcohol produced by fermenting corn and other carbohydrate-rich crops: Added to gasoline to reduce automotive emissions Automakers are producing flexible fuel vehicles that run on 85% ethanol and 15% gasoline. Biodiesel = produced from vegetable oil, used cooking grease, or animal fat: Used in cars with diesel engines Cuts down on emissions compared with petrodiesel

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Biodiesel Biodiesel has fewer emissions than petroleum-based diesel.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Biopower processes Biomass is usually converted to biopower through combustion, which creates steam to generate electricity. It is also combined with coal through co-firing. Anaerobic breakdown waste produces methane. Through gasification, biomass is vaporized to generate electricity. Pyrolysis results in an oil that can be burned for electricity.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pros and cons of biomass PROS: Releases no net carbon into atmosphere Renewable as long as forests aren’t depleted Capturing methane reduces its emissions. Biofuels reduce pollutant emissions. Usually inexpensive Some waste can be used for energy. CONS: Traditional burning methods cause indoor air pollution. Fuelwood harvesting can cause deforestation, erosion, etc. Growing crops establishes monoculture agriculture. Farming corn and other biofuel inputs requires fossil fuels and industrialized agriculture. Growing crops for fuel (e.g., corn for ethanol) is inefficient.