m25.    How is solar energy used?

Active solar heating has specifically designed collectors and a fan or pump. By 2030 parabolic dishes may track the sun and focus it onto a single point to produce electricity for about 5 cents per kilowatt-hour. Solar power plants need large collection areas by use of less land than coal-burning plants and 95% less land per kilowatt-hour than most hydropower projects. Photovotaic cells are layers of purified silicon. The government cut R&D budget by 76% between 1981 and 1990; the US share of the world market in solar cells fell from 75% to 32%.

g06.    What are some of our energy resources?

g13.    What makes up earth's climate?

g18.    What is energy?