Renewable Energy

1. Renewable Energy Section 1- Renewable Energy Today

2. Renewable Energy • Energy from sources constantly being formed • Use needs to be increased

3. Solar Power • Sun • Passive Solar Heating • Uses heat from sun directly • Large windows face directly into sun • N. hemisphere- south windows

4. Solar Power • Active Solar Heating • Gathered by collectors • Usually mounted on roof • Heats water in collector and transfers throughout home

5. Solar Power • Photovoltaic Cells- solar cells • Use sun energy to produce a small amt. of electricity • Can be stored in batteries • Efficient and less expensive • Good for developing countries

6. Wind Power- Cheap and Abundant • Uneven heating from sun causes wind • Wind turbines can convert into electricity • Cheap • Wind Farms- Large arrays of wind turbines • Problem transporting electricity from rural to urban areas

7. Wind Farm

8. Biomass- Power from Living Things • Biomass fuel- any organic matter used for energy • Ex: Wood, organic trash and manure • Burning can release air pollution • Methane gas from decomposition

9. Biomass- Power from Living Things • Alcohol- Liquid fuel derived from biomass • Ethanol- from fermenting fruit or agricultural waste; corn is major source • Gasohol- gasoline + ethanol • Less air pollution

10. Hydroelectricity- Power from Moving Water • 20% of world’s electricity • Dams hold water- reservoir • Released to turn a turbine • Benefits: • Inexpensive • No air pollution • Last longer than power plants • Provide: flood control, drinking water, agriculture, industry, and recreation

12. Hydroelectricity- Power from Moving Water • Disadvantages: • Disruption of ecosystems; Ex: Salmon • Displacement of people • Farmland below dams less fertile • Future: • Micro-hydropower- Floating turbine in a small stream

13. Geothermal Energy- Power from the Earth • Energy from heat in the water deposits of the earth’s crust • Geothermal pumps- heated water to turbine and recycle back for reheating • U.S. world’s largest producer • Ex: The Geyser’s in CA-1.7 million houses

14. Geothermal Energy

15. Geothermal Heat Pumps- Energy for Homes • 600,000 homes in U.S. • Stable underground temperatures year-round allows for heating and cooling all year • Ground cooler in summer and warmer in winter

16. Geothermal Heat Pump

17. Chapter 18- Renewable Energy Section 2- Alternative Energy and Conservation

18. Alternative Energy • Energy sources that do not use fossil fuels and are still in development • Viable if cost effective and environmental effects are acceptable • Research with gov’t investment

19. Tide- movement of water caused by gravitational b/w sun, moon and Earth Twice a day, rise and fall Used to generate electricity in France, Russia and Canada France and Britain used over 1000 yrs ago High tides come in, trapped by a dam After low tide, dam opens to allow water to rush out spinning a turbine to generate electricity Cost is high to build and maintain Few siutable locations Tidal Power

20. Tidal Power

21. Ocean Thermal Energy Conversion • Warm surface water boils sea water at low temp. in a vacuum • Steam spins a turbine to generate electricity • Cold water from deep ocean cool steam back into liquid to be used again • Not cost effective and effects of pumping large amounts of cold water to surface are unknown

22. Ocean Thermal Energy Conversion

23. Hydrogen- A Future Fuel Source? • Most abundant element in universe can be burned as fuel • No carbon-no pollution! • When burned combines with oxygen to form water vapor and nitrogen oxide • Can split molecules of water or grow plants to produce hydrogen cost effectively

24. Challenge of Hydrogen Fuel • Takes a lot of energy to produce • Use of fossil fuels to split atoms pollutes • Can use solar or wind power • Can store in tanks and transport in pipes • Could use as it is produced in fuel cells

25. Fuel Cells • Produces electricity chemically by combining H with O • Can be fueled by anything w/ large amounts of H, such as gasoline, natural gas and alcohol • Could continue to use gasoline stations

26. Energy Efficiency • Percentage of energy put into a system that does useful work • Energy efficiency = Energy Out X 100 Energy In • First Law of Thermodynamics- Energy in must equal energy out; much lost as heat

27. Energy Efficiency • Over 40% of commercial energy is wasted • Fuel-wasting vehicles, furnaces, and appliances • Leaky, poorly insulated buildings • Could save by: • Fuel cells instead of internal combustion engines • Increase public transportation • Fluorescent instead of incandescent lights

28. Hybrid Cars • Small, efficient gasoline engines with also an electric motor for extra power • Convert braking energy into electricity to store in battery • Shut off gas engine to save fuel when sitting • Aerodynamics make less energy for acceleration • Cost a little bit more, but less to refuel and pollute less

29. Hybrids

30. Cogeneration • Production of two useful forms of energy from same fuel source • Ex: Waste heat from an industrial furnace can run a steam turbine for electricity • Can supply heat and electricity to multiple buildings • Small units now available in U.S.

31. Cities and Towns Plug leaks around windows and doors Replace inefficient furnaces Insulate water heaters EX: Osage, Iowa saved over $1 million a year; boosted economy Around the Home $1,200/year per home; lost energy through poor insulation Seal doors and windows (replace w/high efficiency windows) Energy Conservation-Saving Energy

32. Save Energy Around the Home

33. Use less of any resource to save energy Wash clothes in cold water for less energy usage (25% of heat usage) Conservation Tips: Walk or ride a bike on short trips Carpool or use public transportation Drive a fuel-efficient automobile Choose ENERGY STAR* products Recycle and buy recycled products Set computers to sleep mode when not in use Conservation in Daily Life