1. Energy from sources that are constantly being formed
Renewable energy
Energy from sources that are constantly being formed

2. Solar Energy Power from the sun
Produced by nuclear fusion reactions in the sun’s core
Passive Solar Heating:
Uses the sun’s energy to heat something directly
Oriented according to the yearly movement of the sun
Active Solar Heating:
Energy from the sun is gathered by collectors & used to heat water or to heat a building
Photovoltaic Cells:
Convert the sun’s energy into electricity
Energy is stored in batteries which supply electricity when the sun is not shining

3. Passive Solar Heating

4. Active Solar Heating

5. Wind Power Converts the movement of wind into electrical energy
Fastest growing energy source in the world
Cost has declined
Problem with transporting electricity

6. Biomass
Using plant material, manure & any other organic matter as an energy source
Methane
Produced when bacteria decompose organic wastes
Can be burned to generate heat or electricity
Alcohol
Produced by fermenting fruit or agricultural waste (ex: ethanol from corn)

7. Hydroelectricity Produced from the flow of moving water
20% of the world’s electricity
Water in a reservoir is released to turn a turbine, which generates electricity
Expensive to build, relatively inexpensive to operate
Doesn’t contribute to acid rain
Dams last longer than most fossil fuel power plants do
Changes a river’s flow & can disrupt ecosystems

8. Hydroelectricity

9. Geothermal The energy from heat in the Earth’s crust
Power plants pump heated water or steam from rock formations and use the water or steam to power a turbine that generates electricity
Water must be managed carefully so it is not depleted
Geothermal heat pumps can be used to both heat & cool homes

10. Geothermal

11. Alternative energy and conservation
Section 18-2
Alternative energy and conservation

12. Alternative Energy Energy sources that are still in development
2 conditions that must be met for an alternative energy source to become a viable option for the future:
Cost effective
Environmental effects must be acceptable

13. Alternative Energy Technologies
Tidal power
Ocean thermal energy conversion
Hydrogen

14. Alternative Energy

15. Energy Efficiency
The percentage of energy put into a system that does useful work
More than 40 % of all commercial energy used in the U.S. is wasted. Most of it is lost from inefficient fuel-wasting vehicles, furnaces, and appliances and from leaky, poorly insulated buildings.

16. Conservation Around the Home
Energy conservation: saving energy