Hydroelectric Power Explained

By Sam K Weller

We've all heard of hydropower, and it is, in fact, the largest form of renewable energy in the world, producing 21 per cent of the renewable energy and supplying over one-seventh of the earth's population with power. Hydropower is the name of electricity generated from the gravitational force of water.

Hydropower is a very positive source of energy as it produces few fossil fuel, or greenhouse gases. Hydropower has a long history of usage, though the first plant as we know it was built in 1878. The first half of the 20th century saw a number of hydropower plants built, especially in the USA, which saw some colossal developments of this form of power.

The largest dam, however, in the world producing this sort of power is in China - The Three Gorges Dam. Hydroelectricity is producing increasing amounts of China's domestic and business energy, with many more dams planned. In some countries, hydro, electric power will supply 85 per cent of their energy needs meaning the end of requirements for fossil-fuel domestic and business energy. Countries with large amounts of running water such as Norway and Paraguay expect this to be the case.

Hydroelectricity power is created through a number of different methods. The most common power comes from dams and builds up and funnels water with a dam. This water is used to drive a water turbine and creates electricity.

Pumped storage uses a method of supply and demand for power and two reservoirs at different elevations to create power. When demand for energy is low, water is pumped into the higher reservoir and when demand is high this water is released to the lower reservoir and ran through a generator on the way to create power. Run of the river systems, where the flow of the river is used with a turbine and tidal systems where the rise and fall of the tide produce power also exist.

There are a number of pluses for using this form of power generation - one of the most obvious being cost. There is no need for fuel with hydroelectric power and no need for fossil-fuel fluctuations, or imports to be considered. The plants also last long periods and are usually automated. These dams cost little to build and return their investment in a number of years.

Once again, the fact hydroelectric power does not need fossil fuels means it is a positive. These dams don't create CO2 directly. In fact, hydroelectricity produces the least amount of carbon dioxide of any source when production, construction and running come into consideration according to a study by the University of Stuttgart.

Reservoirs can also be used for a number of other positive uses, such as for fishing, sports and irrigation. They can be constructed to control areas prone to flooding and prevent it. They do, however, need large areas of land and submerge a once dry area in water. This affects the natural surroundings and the local environment. They do dissolve the oxygen content of water, which can damage fish. People may have to relocate because of this.

Reservoirs often become full of sediment as the water is carrying silt, but going nowhere and it all eventually deposits in the area - this can cause problems for the dam. Finally, if a dam breaks it ends up as a natural disaster on a huge scale and people can be killed in their masses. Hydroelectric power has its positives and negatives. However, still is one of the most important sources of power in our world and can be used for both domestic and business energy.