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

Hydroelectric power In hydroelectric power, moving water is used to turn turbines and generate electricity. The storage technique stores immense amounts of water behind dams.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydroelectric power For nations with large amounts of flowing water (Brazil, Norway, Austria, Canada…), hydropower has been key to their economic development. 98% of U.S. rivers are dammed. Turbine generator inside dam

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydroelectric power

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydroelectric power Water flowing through a dam spins turbines that turn generators to create electricity.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Hydroelectric power Run-of-river systems divert only a portion of a river’s water.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pros and cons of hydroelectric power PROS: Renewable as long as water is not overdrawn from river system Clean: no greenhouse gas emissions CONS: Dams cause numerous disruptive ecological effects to riparian environments. Dams thus bring a mix of impacts for people.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Conclusion Given limited supplies of fossil fuels and their environmental impacts, many nations are pursuing alternative energy sources. The three most widely used alternatives so far are nuclear power, biomass energy, and hydropower. Because of high costs and public fears over safety, some nations are attempting to phase out nuclear power. Biomass sources can be carbon-neutral but are not all strictly renewable. Hydropower is renewable and pollution-free, but it is nearing its maximal use and can involve substantial ecological impacts.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Biomass accounts for how much of the energy consumption in the U.S.? a.>85% b. 2.8% c. 20% d..5%

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which of the following is not a characteristic of breeder nuclear fission? a. Uses plutonium b. Generates less power than nuclear fission c. Produces less waste than nuclear fission d. Raises the risk of explosive accidents

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which of the following is not a drawback of nuclear power? a. Its waste is dangerously radioactive. b. Consequences of accidents can be catastrophic. c.It is expensive to produce. d.It pollutes more than fossil fuels.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review What are the two biggest benefits of hydropower? a.Renewable, gentle on nearby ecosystems b. Produces no greenhouse gases, protects fish c.Renewable, produces no greenhouse gases d.Renewable, protects fish

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Weighing the Issues If you were the leader of a major developed nation, in which conventional energy alternative would you direct the greatest investment? a.Nuclear power b.Biopower c.Hydropower d.Biofuels

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data For what pollutant does pure biodiesel provide the greatest level of reduction versus petrodiesel? a. Particulate matter b. Carbon monoxide c. Hydrocarbons d. Sulfates

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data What does the table tell us about the geography of each nation? a. Larger nations consume more hydropower. b. Nations with more rivers consume more hydropower. c. Populous nations generate more electricity from hydropower. d. None of the above

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Viewpoints Do the benefits of nuclear power outweigh its drawbacks? a.Yes; reducing greenhouse gas emissions should be a top priority. b.No; the potential catastrophe is too large. c.No; energy security is achievable using other renewable sources. d.It depends on a country’s existing energy supply and its need for alternatives to fossil fuels.