4.2 – Alternate Energy Sources

Do Now What are three examples of alternate energy resources?

Do Now What are three examples of alternate energy resources? Solar Nuclear Wind Hydroelectric Geothermal Tidal

Key Words Advantage Disadvantage Inexhaustible

Vocab Words Geothermal Energy Hydroelectric Power

Alternate Energy Sources At the present rates of consumption, the amount of recoverable fossil fuels may last only another 170 years. As the population soars, the consumption will climb. Our growing demand for energy along with our need for a healthy environment will likely lead to a greater reliance on alternate energy sources.

Solar Energy The most abundant energy resource. Every second, the total energy that comes from the sun amounts to more than 10,000 times the total amount of energy used by all humans in a day. Advantages: the “fuel” is free, and it’s non-polluting. Disadvantages: very expensive to install and will only work well in areas with a lot of average sunlight.

Solar Energy

Nuclear Energy Nuclear Power meets about 7% of the energy demand of the United States. The fuel for nuclear plants comes from radioactive materials that release energy through nuclear fission. In nuclear fission, the nuclei of heavy atoms such as uranium-235 are bombarded with neutrons. The uranium nuclei split into smaller nuclei and emit neutrons and heat energy. Advantages: Only requires a small amount of fuel to generate a lot of power and it is cheap, clean energy. Disadvantages: Cost of building is expensive, hazards associated with nuclear waste and possibility of radioactive materials to escape.

Nuclear Energy

Wind Energy Wind energy is not a new energy source, people have been using windmills as a source of energy for centuries. In the next 50 to 60 years, wind power could meet between 5 to 10 percent of the country’s demand for electricity. Advantages: If you live in a windy area the “fuel” is free and only takes a small amount of wind to generate a lot of electricity. Disadvantages: Noise pollution and the cost of land in populated areas.

Wind Energy

Hydroelectric Power Hydroelectric power is the power generated by falling water. Produces 5% of the country’s electricity comes from hydroelectric power. The water held in a reservoir behind a dam is a form of stored energy that can be released through the dam to produce electric power. The strong water flow that results drives turbines and electric generators. Advantages: Water is a renewable resource and the dams help control the flow of rivers. Disadvantages: Suitable sites are a limiting factor, hydroelectric dams have finite lifetimes because sediment builds up behind the dam.

Geothermal Energy Geothermal energy is harnessed by tapping natural underground reservoirs of steam and hot water. Hot water is used directly for heating and to turn turbines that generate electric power. Advantages: Power is clean and provides electrical power with little environmental impact. Disadvantages: Sources can be diminished and be gone for forever and are limited to certain areas that have geothermal fields.

Tidal Power Tidal power is harnessed by constructing a dam across the mouth of a bay or an estuary in coastal areas. The strong in-and-out flow of tidal water drives turbines and electric generators. Advantages: a small tide can generate a lot of energy and only takes a small area to provide power to a large area. Disadvantages: is very site specific and can potentially cause harm to intertidal zones and marine life.

Group Challenge Question Why will the interest in alternate energy sources probably grow in the future?