Energy- renewable’s

Students will be able to identify the pros and cons for the 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

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

• Can be used anywhere

Disadvantages

• CO2 still released when it is burned. (But this is currently part of the current carbon cycle already)

• Farm land used for fuel, thus not as much 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

Fuel Cell

• Fuel cells use hydrogen and oxygen to make water. Electricity is produced in the process.

Fuel CellAdvantages• No pollution – just water!• Quiet• Doesn’t use up fossil fuels• Can be used in cars

Disadvantages• Most hydrogen has to be

produced by breaking apart water molecules and that TAKES energy.

• Hydrogen gas is very flammable and explosive

http://www.brainpop.com/technology/energytechnology/fuelcells/ (greenwichps / gps2009)