Renewable Energy - Hydropower

Hydropower, the energy that comes from the natural flow of water, is the world's largest renewable energy source. The energy of falling water or flowing water is converted into mechanical energy and then to electrical energy. In the past, flowing water turned waterwheels to grind grain or turn saws, but today flowing water is used to turn modern turbines. Hydropower is a renewable, nonpolluting, and reliable energy source.

Advantages and Disadvantages of Using Hydropower Energy

At present, hydropower is the only means of storing large quantities of electrical energy for almost instant use. This is done by holding water in a large reservoir behind a dam, with a hydroelectric power plant below. The dam creates a height from which water flows. The fast-moving water pushes the turbine blades that turn the rotor part of the electric generator. Whenever power is needed at peak times, the valves are opened, and turbine generators quickly produce power.

Nearly all the best sites for large hydropower plants are already being put to use in the United States. Small hydropower plants are expensive to build but eventually become cost-efficient because of their low operating costs. One of the disadvantages of small hydropower generators is their reliance on rain and melting snow to fill reservoirs because some years bring drought conditions. Additionally, U.S. environmental groups strongly protest the construction of new dams in America. Ecologists express concern that dams ruin streams, dry up waterfalls, and interfere with aquatic life habitats.

New Directions in Hydropower Energy

The United States and Europe have developed a major proportion of their hydroelectric potential. Large-scale hydropower development has slowed considerably in the United States. The last federally funded hydropower dam constructed in the United States was the Corps of Engineers' Richard B. Russell Dam and Lake, which is located on the Savannah River and borders South Carolina and Georgia. The project was authorized in 1966 and completed in 1986. However, expansion and efficiency improvements at existing dams still offer significant potential for additional hydropower capacity and energy. Until recently in the United States, dams were usually funded entirely with federal monies. Since 1986, however, local governments must contribute half of the cost of any new dam proposed in the United States. Hydropower's contribution to U.S. energy generation should remain relatively constant, although existing sites can become more efficient as new generators are added. Any new major supplies of hydroelectric power for the United States will likely come from Canada.

Most of the new development in hydropower is occurring in the Third World, as developing nations see it as an effective method of supplying power to growing populations. Most of these hydropower-development programs are massive public-works projects requiring huge amounts of money, which is mostly borrowed from the developed world. Third World leaders believe that hydroelectric dams are worth the cost and potential environmental threats because they bring cheap electric power to their citizenry.