Hydroelectric dams and reservoirs accounts for 20% of the the worlds generated electricity making it the number one renewable and green energy source provider. The figure is likely to grow over the next few decades as although it is oldest form of electrical generation there are still areas for improvement, notably in losses due to friction and turbine design.
Hydro electricity requires a reliable supply of water. This is achieved by creating a stock of water called a reservoir by building a dam. The water from the reservoir is released through a pipe called a penstock, to drive the turbine. Turbines are in effect just a propeller mounted on a shaft. On the other end of the shaft is the generator which is made from coils of copper wire and magnets. It is the generator that produces the electricity which supplies the power for your home.
Reservoirs are created to give a steady supply of water
Hydroelectric dams are usually concrete structures but depending on the geography and stresses involved they could be made from earth. Some Hydroelectric dams use both earth and concrete, especially in cases where several separate dams need to be constructed to make a reservoir (types of dam). The siting of a dam has to be carefully considered as the weight of the structure can be quite immense. Depending on the geography of the land surrounding the reservoir to be created, will dictate the type of hydroelectric dams to be built. Low and long dams will normally be made from earth and rock whereas narrow dams which need to be high will be made from re-enforced concrete.
The type of turbine is another crucial factor in designing a hydro electric facility. There are several types and each has better performance outputs relating to the force and amount of water being supplied.
Producing hydro generation does not mean it has to be big. There are many situations where it is practical to make a small dam to supply just a single household so long as a sustainable supply of water may be stored. The cost per Kwh or unit of electricity is generally more expensive on small scale hydro generation but the reward of being self sufficient can out weight the extra expense. It is also possible that a home hydro electric generator may have a surplus of electricity and this may be sold back to the electricity grid for either a profit or to help offset the cost of running ones own system.
Problems can develop on an environmental level as creating the hydroelectric dams or reservoirs will have an effect on the local ecology. Objections may arise to the loss of habitat and loss of wildlife and fauna though there is reasonable grounds to suggest that this ecology would suffer far more in the continued use of fossil fuels.