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
Think: how could tidal power harm sea life?
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

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
How much energy does the US use compared to the world average?
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.