With the growing concerns over the environmental problems today (air pollution, global climate change, massive flooding in river systems, etc.) and the price of non-renewable energy sources soaring, we have to take a closer look at the alternative energy sources . Alternatives to the fossil fuels and nuclear power are renewable sources of energy and they are considerably more attractive in many ways. Renewable sources are derived and replenish quickly from nature and usually do not pollute our environment when used to generate electricity. The five renewable sources used most often include hydropower (water), solar, wind, biomass, and geothermal.