Chapter 18 Renewable Energy Sources

1. Chapter 18 Renewable Energy Sources

2. Cleaner Cars, Cleaner Fuels • Cars release a lot of pollution • 2005 • Bush administration • 7% improvement in mileage • 22.2 mpg • 2020 30.5 mpg • Diesel engines need work

3. Cleaner Cars, Cleaner Fuels • Energy Policy Act of 2005 • Tax credits • Energy-efficient autos • Liquid hydrogen as a fuel • What does the future hold?

4. Electrical Generation Costs

5. Direct Solar Energy • Energy directly from the sun • Tremendous amount • Always available • Must be collected

6. Active Solar Heating • Collectors absorb solar energy • Pumps or fans distribute heat • Primarily for heating water

7. Passive Solar Heating • No mechanical devices to distribute heat • New home design • Room temperature is steady • Convection • Save on heating!

8. A Passive Solar Home

9. Photovoltaic (PV) Solar Cells • Convert sunlight into electricity • Thin wafers or films • No pollution • Minimal maintenance

10. Photovoltaic (PV) Solar Cells • Can be used in remote areas • Good choice for developing countries: why? • School, home use

11. Photovoltaic (PV) Solar Cells • Can look like conventional roofing • Prices are coming down • Future progress is critical

12. Solar Thermal Electric Generation • Sun’s energy concentrated by mirrors, lenses • Heat a working fluid • Fluid is circulated to boil water • Steam generates electricity

13. Solar Thermal Electric Generation • Backup system needed • Very efficient • No pollution produced • Must be cost- competitive

14. Hydrogen As A Fuel Source • Could be the fuel of the future • Where does the hydrogen come from? • Electrolysis • Must use renewable fuel source to obtain the hydrogen! • Few pollutants produced when burned • Can be used for transportation

15. Solar-Generated Hydrogen • Use PV cells for electrolysis of water • Currently not very efficient • Still expensive • Would need new distribution system for transportation • Future development is critical

16. Solar-Generated Hydrogen • Fuel cells • Electrochemical cell • Like a battery • Major carmakers working on it

17. Indirect Solar Energy • Indirect use of sun’s energy • Biomass, wind power, hydroelectricity

18. Biomass Energy • Wood, plants, animal wastes • Potentially renewable: why? • Burned to release energy • Half of human population relies on • Cooking, heating

19. Biogas • Mixture of gases • Similar to natural gas • Animal wastes • Biogas digesters • Decompose wastes • Use gas for cooking, lighting • Solid remains are fertilizer • Can also be used to power fuel cells

20. Biogas Digester

21. Biomass As A Liquid Fuel • Methanol, ethanol • Gasohol: mix gasoline and ethanol • Biodiesel • Plant, animal oils • Becoming more popular • Burns cleaner than regular diesel

22. Ethanol • Sugarcane, corn, wood, agricultural and municipal wastes • Government subsidizes • Good outlet for some wastes • Problems • Land and water use • Soil erosion • Decreased food production

23. Wind Energy • Fastest growing energy source • No waste, emissions • Electricity • Costs are declining • Denmark is a world leader • Need steady winds • Great Plains of U.S.

24. Wind Power Is On The Rise!

25. Wind Energy Problems • Birds and bats killed by turbines • Avoid migration routes • Operate only at certain times • Monitor the project • Visual pollution • Maple Ridge, NY • Massachusetts coast

26. Hydropower • Flowing or falling water spins turbines • Most efficient way to produce electricity • 19% world’s electricity • 2200 U.S. plants

27. Hydropower Problems • Damages ecosystem, species • Displaces people: Three Gorges Dam • High construction cost • Reduces downstream flow • Reservoirs eventually fill in • Danger of collapse • Degrades river • Increase in waterborne disease: schistosomiasis

28. Geothermal Energy • Use energy from Earth’s interior • Big potential source • Electricity • Hydrothermal reservoir: hot fluid • Bring fluid to surface to generate electricity

29. Geothermal Energy

30. Geothermal Energy • Emits very few pollutants • Is it truly renewable? • Land may subside

31. Geothermal Heat Pumps • Used for heating and cooling • Ground temperature relatively constant • Underground pipes carry water • Fluids circulate • Expensive to install • Use is on the increase: why? • Very efficient!

32. Tidal Energy • Use power of the tides to generate electricity • France, Russia, China, Canada • Very few ideal locations • May be damaging to ecosystems

33. Conservation & Efficiency • Energy conservation • Using less energy • Reduce use, waste • Carpooling • Energy efficiency • Using less energy for a task • More fuel-efficient cars • Both very important!

34. Energy Consumption Trends • Use is on the increase • Greatest increase in developing countries: why?

35. Energy-Efficient Technologies • Appliances, automobiles, light bulbs, furnaces, etc… • “Superinsulated” buildings • May cost more, but will save money!

36. Energy-Efficient Technologies • National Appliance Energy Conservation Act • Sets national standards • Much greater efficiency today • Invest in energy improvements now to save money in the long run

37. Automobile Efficiency • Has improved since 1970s: why? • Increased use of minivans, trucks, SUVs • Efficiency must continue to improve

38. Cogeneration • Combined heat and power (CHP) • Recycling “waste” heat • Generate electricity, use steam before cooling it back down

39. Electric Companies & Energy Efficiency • Make more money, generate less electricity • Incentives for conservation • Help consumers save electricity • Light bulbs, furnaces • Company doesn’t have to invest in new power generation

40. Electric Companies & Energy Efficiency • Use cogeneration to save energy • Improve electricity grids • Some energy lost in transmission • Plan for future use

41. Energy Conservation At Home • Average household: $1500/year on utilities • Use energy-efficient technologies • Better insulation, windows • Seal cracks • Replace inefficient appliances

42. Energy Conservation At Home