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Transcript of Energy- The Renewable’s Students will be able to identify pros and cons for renewable and...
Energy- The Renewable’s
Students will be able to identify pros and cons for renewable and
nonrenewable energy sources.
Looking back…
What types of non-renewable energy have we discussed?
• Fossil fuels - Coal- Natural Gas- Petroleum
• nuclear power
Benefits of Fossil Fuels
• Able to generate large amounts of electricity• Convert approx. 40% of energy to electricity• Location not very limited (only to
transportation)
Drawbacks
• Nonrenewable – We will run out!• Coal produces SO2- acid rain
• Crude oil- poses environmental hazards (Spills)• Coal mining causes destruction of land• Pollution!- CO2
Much air pollution is caused by the burning of fossil fuels…
Nuclear Energy
Benefits• Emission-free energy
– No GHGs or particulates
• Generates large quantities of energy
Drawbacks• Limited amount available• Radiation if meltdown
occurs
Estimated 3,256,000 tons uranium that is recoverable.
75,000 tons/year to produce 17% of the world power requirements
Only enough to meet energy demands for 42 years.
What will happen when these are gone?
Renewable Energy
Solar Power
Benefits-No Pollution!-Can be installed on rooftops (save space)-After initial installation, the cost is low
Drawbacks-Only generates electricity during daylight-Efficiency affected by weather (cloudy/hazy days)-Inefficient- 10% sun’s energy is converted
Solar PowerEnergy from the sun on a
surface directly facing the sun
Wind Power
Benefits-Clean energy (no pollution)-Renewable-35% energy
efficiency
Wind Power
Drawbacks-Wind isn’t dependable-Unable to function in bad weather-Blades can be damaged-Considered to be an eyesore by some-Loud-Kills birds and bats
Wind Power
Cape Wind Controversy
Proposed wind farm off the shore of Nantucket Sound’s Horseshoe Shoal
Hydropower
Hydropower
Benefits-Requires little maintenance to operate-Plants last a long time (at least 50 years)
Hydropower
Drawbacks-Requires a strong river to be dammed-Can be destructive
- Flood large areas and cut off streams
-Dams cut migrating fish off from their spawning areas
Three Gorges Dam, China
Flooded 13 cities, 140 towns, 1,350 villagesSubmerged factories waste to be introduced into the reservoir
How much power can one dam produce?
The Three Gorges dam produces as much energy each year as:
25 million tons of crude oil
50 million tons of coal
15 nuclear power plants
Geothermal Energy
Use of heat from within the Earth.-Steam or hot water
Geothermal resources in US
Drawbacks•Location dependent• Potential danger of
noxious gases• Noise problems from
steam valves
Geothermal Energy
Benefits•Emit water vapor (no air pollution!)•Generates continuous power
Current Status for Geothermal Energy
Geothermal power could serve 100% of the electrical needs of 39 countries (over
620,000,000 people) in Africa, Central/ South America and the Pacific.
Today, about 95% of the buildings in Reykjavik are heated with geothermal water. Reykjavik is
now one of the cleanest cities in the world.
U.S. Geothermal Potential
Biofuel
• Energy from plants• Organic material converted into a combustible
fuel– Example: Corn
or sugar cane converted to ethanol
Biofuel
Advantages• Easy to grow• Can convert waste
parts of plants into fuel
• Mixed in with or used instead of gasoline, thus saving fossil fuels
Disadvantages
• CO2 still released when it is burned. (But this is part of the current carbon cycle already)
• Farm land used for fuel, less food produced
• Sometimes the amount of energy needed to harvest, convert, and transport the fuel uses as much oil as it saves.
Brazil is a leader in biofuel 50% of its vehicles can run on 100%
biofuel