Nuclear power and hydropower are common methods by which large amounts of electricity are generated for use by consumers. According to the U.S. Department of Energy, in 2008, nuclear accounted for about 11 percent of the energy generated in the U.S., while hydropower accounted for 6 percent. Both are relatively clean and inexpensive methods of energy production although, if used improperly, both can create environmental problems.


Hydropower has been used in some form, for over two millennia. The ancient Greeks first used wheels powered by water to crush grain and corn. The first modern hydroelectric power plant went into operation in 1882 on the Fox River in Appleton, Wisconsin. Nuclear power is a much newer technology, with the first electricity generated by a nuclear reactor near Arco, Idaho, and the first plant coming online in 1954, in Obninsk, Russia.


Hydropower and nuclear power produce electricity through the spinning of turbines. In hydropower, water passes through turbines in a dam; these turbines in turn spin a generator, producing electricity. In nuclear power, radioactive rods heat water, which produces steam; this steam spins turbines, which like hydropower, spins a generator, producing electricity.


Hydropower and nuclear power have allowed geographic areas that do not have easy access to other cheap electricity-generating resources, such as deposits coal and natural gas, to produce power. The recent increase in concern over climate change has also led to renewed calls for more hydropower and nuclear power, both of which produce almost no greenhouse gas emissions.


Nuclear and hydropower are relatively inexpensive. Although the capital cost of building plants for both technologies is relatively expensive, once they begin running, they cost little to maintain, given that uranium, the fuel that powers most nuclear plants, is generally cheap, and water is all but free.


Hydroelectric power has many advantages: it produces very little pollution; it is affordable; and the plants are energy-efficient, require little maintenance and are easy to stop and start. Besides being inexpensive, nuclear power produces little air pollution or greenhouse gases and can be contained in a small space.


Nuclear and hydropower have some significant drawbacks, due largely to possible environmental consequences. While nuclear power is generally safe -- after 50 years, there has not been a single recorded death in the U.S. that can be traced to nuclear power -- the waste that is a produced as its byproduct is highly toxic and difficult to dispose of. While hydropower is non-polluting, the dams that must be built to create it can, if sited improperly, destroy entire habitats of plants and animals.