1. 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. Tidal Power
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

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 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. Energy Conservation-Saving Energy
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)

32. Save Energy Around the Home

33. Conservation in Daily Life
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
Use less of any resource to save energy
Wash clothes in cold water for less energy usage (25% of heat usage)