Primary energy sources used in electrical power generation

The world relies mainly on coal and natural gas for power. The high capital requirements of nuclear power and the fear of its dangers have prevented the ordering of new nuclear power plants in North America since the 1970s.

Steam turbines can be powered using steam produced from geothermal sources, solar energy, Nuclear reactors use the energy created by the fission of radioactive plutonium or uranium to generate heat. They often use a primary and secondary steam circuit to add an additional layer of protection between the location of the nuclear fuel and the generator room.

Hydroelectric power plants use water flowing directly through the turbines to power the generators.

Tidal harnesses use the force of the moon on bodies of water to spin a turbine. Wind generators use wind to turn turbines that are hooked up to a generator. Pumped-storage hydroelectricity is used to level demands on the power grid. Power generation by thermonuclear fusion has been suggested as a possible way of generating electricity; currently a number of technical obstacles and environmental concerns stand in the way, but if realized fusion might provide a relatively clean and safe source of electrical power. The construction of a large experimental reactor (ITER) is expected to commence in 2005-

2006. (From Wikipedia, the free encyclopedia). http://en.wikipedia.org/wiki/Electrical_generation

Advantages and Disadvantages of Hydro Systems

The chief advantage of hydro systems is their capacity to handle seasonal (as well as daily) high peak loads. In practice the utilisation of stored water is sometimes complicated by demands for irrigation which may occur out of phase with peak electrical demands. Times of drought can cause severe problems, since water replenishment rates may not keep up with desired usage rates.

Concerns have been raised that large hydroelectric projects might be disruptive to the surrounding ecosystem. For instance, studies have shown that dams along the Atlantic and Pacific coasts of North America have reduced salmon populations by preventing access to spawning grounds upstream.

The creation of large bodies of water involved with damming rivers for Hydroelectric power is also considered an environmental risk. For example, pine needles that fall in the water can turn the water acidic.

One of the most newly discovered and most troubling environmental consequence of hydroelectric power include the fact that such plants produce substantial amounts of carbon dioxide, and then serve to convert carbon dioxide to methane. This is due to plant material in newly flooded and re-flooded areas being innundated with water, decaying in an anaerobic environment, allowing for the formation of methane, a very potent greenhouse gas. The methane is released into the atmosphere once the water is discharged from the dam and turns the turbines. In some cases, more greenhouse gasses are released from a dam for electricity generation than generating the equivalent amount of energy from burning oil.