Chapter 4 Earth Resources Section 4.2 Alternate Energy Sources

Alternate Energy Sources Solar Energy Nuclear Energy Wind Energy Hydroelectric Energy Geothermal Energy Tidal power

Solar Energy Earths most abundant energy resource Solar energy technologies use the sun’s rays to supply heat or electricity Solar energy is free and nonpolluting

Solar Energy Pros Free Abundant Nonpolluting Cons Costly equipment and installation Supplemental heating is needed during reduced sunlight ie., on cloudy days, in the winter, and at night

Nuclear Energy In nuclear fission,the nuclei of heavy atoms such as Uranium-235 are bombarded with neutrons. The uranium nuclei then split into smaller nuclei and emit neutrons and heat energy.

The Birth of Nuclear Energy “At one time, energy experts thought nuclear power would be the cheap, clean energy source that would replace fossil fuels.”(Tarbuck & Lutgens, 104)

What obstacles slowed the development of nuclear energy?

Set backs for nuclear energy Cost of safe facilities has increased Hazards associated with disposal of nuclear waste Possibilities of serious accidents allowing radioactive material to escape

Nuclear Accidents Three Mile Island, 1979 -low water levels lead to reactor damage Chernobyl, Ukraine, 1986 -much more serious, out of control reactor, fire and explosions, 18 deaths and thousands faced increased risk of death from cancer due to fallout

Wind Energy Wind is not a new energy source Wind turbines harness the most energy in areas with strong steady winds like mountain passes and sea coasts

The Future of Wind Energy 5%-10% of the countries energy needs could be met in the next 50 - 60 years by wind power

Difficulties and obstacles facing wind energy Need for technical advances Noise pollution Cost of large areas of land in populated areas Not practical in all locations

Hydroelectric Energy The power that falling water generates to drive turbines and produce electricity

Hydroelectric energy At a hydroelectric power plant water is held in a reservoir behind a dam. Lake Mead is the largest reservoir in the USA and is held behind the Hoover Dam Hydro electric power plants are limited by the availability of suitable sites

Geothermal Energy Is harnessed by tapping natural underground reservoirs of steam and hot water The heated water is used to turn turbines to create electricity

Tidal Power Is harnessed by constructing a dam across the mouth of a bay or an estuary in coastal areas with a large tidal range. The strong in-and-out flow that results drives turbines and electric generators