Renewable Resources

2. Renewable Resources

3. Renewable Resources • Renewable – naturally replaced in a short period of time • Sunlight • Wind • Water • Biomass • Geothermal • Hydrogen

4. Solar Energy • Constantly gives off energy in the form of heat and light • The source of all renewable energy resources. • Does not cause pollution • Will not run out for billions of years. • Why hasn’t it replaced fossil fuels already? • Only available when the sun is shining • Spread out over the whole world

5. Solar Plants – giant mirrors focus the sun’s rays into huge tanks of water, heating the water – the water boils and produces steam

6. Solar Cells • Solar energy can be converted directly into electricity using solar cells. • Very thin layers of silicon and other materials are layered • Upper and lower parts have negative and positive charges, like a battery • When light hits the cell, electrons move across the layers and produce an electric current.

7. Solar Cells • The amount of energy produced by the solar cell depends on the amount of light available. • Solar cells are used to power lots of small devices • Calculators • Lights • Telephones • It would take more than 5,000 solar cells the size of your palm to power most American homes. • Large solar cells are very expensive and hard to transport

8. Solar Heating Systems • A passive solar system converts sunlight into thermal energy without pumps or fans. • Think of a car sitting in the sun • An active solar system captures the sun’s energy, then uses fans and pumps to distribute the heat.

10. Wind • Wind can be used to turn a turbine, which generates electricity. • Wind generates a lot of power, it is free, and it does not cause pollution.

11. Flowing Water • As water flows over land and into lakes and oceans, it provides another source of energy. • This water can turn a turbine and generate electricity. • Hydroelectric power is electricity produced by flowing energy. • Inexpensive and does not create air pollution • Most suitable rivers have already been dammed, and dams can have negative effects on the environment

12. Biomass Fuels • Biomass fuels are fuels made from things that were once alive. • Wood, leaves, food waste • Biomass fuels can be converted into other fuels. • Corn & sugar can be used to make alcohol; when combined with gas, it can fuel cars and trucks. • Bacteria decompose waste materials and produce methane, which can be used to heat buildings. • Producing alcohol and methane are expensive and it takes trees a long to time to grow.

13. Geothermal Energy • In some places (Iceland, New Zealand) magma heats underground water to boiling and produces steam. • This hot water and steam are valuable sources of geothermal energy. • Unlimited source of cheap energy • Only a few places where magma comes close to Earth’s surface…everywhere else we would have to expensive drilling processes

15. HYDROGEN! • What if there was a way to produce energy that burned cleanly and only produced water as its waste? • There is! • But…. • Almost all of Earth’s hydrogen is in water • If an electric current is passed through the water, it isolates the hydrogen • It takes more energy to get the hydrogen out of water than we get out of the hydrogen • Extra energy from hydroelectric and solar plants can be used to isolate the hydrogen • We just have to find a way to make the process cheaper… maybe you could help!