1. Renewable energy  Alternatives to fossil fuels

2. Which countries consume the most energy? think: How much more energy do Americans use than Chinese?

3. Alternative energy sources  Solar  Wind  Geothermal  Nuclear  Tidal  Hydroelectric  Biofuel  We are searching for other sources of energy  Renewable resources will not run out  Environmental impacts could be much less

4. Solar power  Turning light energy into electricity  Sun produces 10,000 x the amount of energy needed to power the world  Adv: Free, non-pollution  Dis: Expensive to build and install the panels & don’t work at night/ cloudy

5. Wind  Wind is the movement of air caused by the uneven heating of the Earth’s atmosphere.  Pros: non polluting, renewable  Cons: unreliable, many birds have be killed by turbines, loud

6. Geothermal  Heat generated by the Earth’s core  water is pumped deep into the Earth crust where it turns into steam that turns a turbine generating electricity  Pros: renewable, nonpolluting  Cons: not available everywhere, can use up water reserves (unless reclaimed water is used)

7. Nuclear Energy  Nuclear fission: splitting large atoms releases energy  Adv: plenty of fuel, no greenhouse gasses, existing technology  Dis: radioactive waste which causes cancer

8. Tidal power  Building a dam in a bay or estuary to use the tides to turn turbines  Adv: non polluting, renewable  Dis: only available in limited areas, could harm sea life Think: how could tidal power harm sea life?

9. Hydro- electric  Moving water turns turbines to Most rivers are already dammed  Causes problems for fish, downstream habitats

10. Biofuel  Organic matter: food scrap, manure, corn ethanol, algae…  Pros: can be “carbon neutral” or decrease greenhouse gasses, can be a reuse of waste products, renewable  Cons: can increase food prices, may use up too much land or not generate enough energy to be cost effective

12. Reducing energy waste  All forms of energy generation waste energy  Power plants are only 35% efficient  We need to reduce our energy use and energy waste 157 mpg car Think: of 3 ways you can save energy.

13. Summary Review 1.How much energy does the US use compared to the world average? 2.Make a chart of the alternative energy sources listed in this lecture of: what they are, how they are ‘harvested’, and the pros and cons of each.