1. Alternative Energy Sources Chapter 17

2. Hydroelectric Energy -Electricity that is produced from the energy of moving water. -Anything that has mass, and moves, has kinetic energy. -Harnessing moving water is a clean, readily available source of energy. -Has been around for centuries (water wheels) -Roughly 20% of the worlds electricity is generated by flowing water.

3. How it works: -water, behind the dam, is directed towards turbines. -Water pushes against the blades, causes it to spin “run” -This motion is transferred to coils of wires in generators -Coils spin through a magnetic field -Produces electricity

5. The pro’s and con’s of Dam’s Pro’s: -Renewable -Green -Reliable -Flexible -Safe -Flood control -Recreation

6. Cons: -Environmental consequence's -Fish migrations -Habitat destruction -Relocation (includes humans) -Drastic temperature changes -Expensive to build -Droughts

7. Other water sources: -Tides -Tidal surges are a great source of electricity (where available) -Pro’s: renewable, very clean, not typically disrupting normal flow (migrations), -Con’s: limited locations available, eye sore, affect benthic community. -Waves -Movement (up and down) waves create can be used to make electricity -Pro’s: renewable, clean, mostly anywhere -Con’s: expensive and difficult to harness, eye sore

11. Home work!! Read “The Ocean Resource” page 273 Answer questions 1 and 2 on page 273 In 2-3 sentences, explain whether or not this is a feasible solution to energy/water crisis found through out the world.

12. Solar Energy -Energy from the sun (which technically is the source for hydro and wind power as well) -Thermonuclear fusion (where the suns energy comes from) -High temps (on the sun) cause hydrogen nuclei to fuse creating helium nuclei -As helium forms, a loss of mass occurs, which is converted into heat and light energy. -We actually receive a miniscule amount of the energy that is created by the sun. -This energy can be harnessed and used to generate electricity.

13. Pros 1.Renewable 2.Abundant 3.Sustainable 4.Environmentally Friendly 5.Good Availability 6.Reduces Electricity Costs 7.Many Applications 8.Shared Solar 9.Silent 10.Financial Support from Government/State 11.Low Maintenance 12.Technology is Improving

14. Cons 1.Expensive 2.Intermittent 3.Energy Storage is Expensive 4.Associated with Pollution 5.Exotic Materials 6.Requires Space

15. Active and passive solar energy: devices are used to collect, store, and circulate heat produced from solar energy. -In active systems -Tubes, tanks, fluids, pumps, fans, and other stuff are used to collect and distribute -Can be used after the sun sets as well -Make use of collectors (ex. Solar panels) -In passive systems (collected, distributed, and stored naturally) -Relies more on the positioning of the house and windows -Oriented so open facing areas (windows) typical face south

18. Photovoltaic Cells: uses thin wafers of semiconductor material to produce electricity directly from the solar energy -Also called the solar cell -Produces electricity directly -Made of elements like silicon and/or selenium -Two layers, of the semiconductor, sun strikes it, causes electrons to move back and forth…viola electricity. -Very common today, signs, watches, etc…

21. Wind Power -Use of the wind to turn a source to generate electricity. Called aerogenerators. -Same basic pro’s and con’s of solar -Not as constant or steady though -and elaborate storage devices are typically required -Two basic types: -Horizontal axis (traditional) -Vertical axis (can be used in lower wind environments)

24. Geothermal -Heat energy generated within the earth. -Generated by the decay of radioactive elements -Hot enough to melt rock (magma) -Water trapped nears surface create steam (geysers) -Geo is used in areas where this source of heat is closer to the surface -Most of Iceland used geothermal to heat homes -Green houses take advantage of the heat to grow produce all year long -Several countries use it to produce electricity.

25. Pro’s and Con’s Pro’s -Renewable Con’s -Not available everywhere -Air is often polluted with toxic hydrogen sulfide in areas where is available -Mineral waste, salts, and toxic metals, tend to corrode pipes and boilers -Often a lack of water in these areas.

27. Nuclear Fusion -Occurs when two atomic nuclei fuse to become one larger nucleus. -Same process found on the sun -Scientist have not yet learned how to control and harness this energy. -Fuel for nuclear fusion is usually deuterium (a hydrogen isotope, readily found in the ocean) -Subjected to enormous pressure and temperature (magnetic field or a laser) Pro’s: less radio active waste, easier to obtain fuel. Con’s: technology not ready for it.