Small Hydroelectric Power

Small hydroelectric power (small hydro) is the application of hydroelectric power on a commercial scale serving a small community or medium sized industry. A generating capacity of up to 10 megawatts (MW) is becoming generally accepted as the upper limit of what can be termed small hydro.

Hydroelectric power is the technology of generating electric power from the movement of water through rivers, streams, and tides. Water is fed via a channel to a turbine where it strikes the turbine blades and causes the shaft to rotate. To generate electricity the rotating shaft is connected to a generator which converts the motion of the shaft into electrical energy.

Small hydro is often developed using existing dams or through development of new dams whose primary purpose is river and lake water-level control, or irrigation. A small-scale hydroelectric facility requires a sizeable flow of water and a reasonable height of fall of water, called the head. Small scale hydro power systems can be installed in small rivers or streams with little or no discernible environmental effect on things such as fish migration. 

Small hydro can be further subdivided into mini hydro, usually defined as less than 1,000 kW, and micro hydro which is less than 100 kW. 

Micro hydro is often used in water rich areas as a Remote Area Power Supply (RAPS), and is frequently accomplished with a pelton wheel for high head, low flow water supply. 

Micro hydro has been increasingly used as an alternative energy source, especially in remote areas where other power sources are not viable. They can complement photovoltaic solar energy systems because in many areas, water flow, and thus available hydro power, is highest when solar energy is at a minimum.

There are some considerations in a micro hydro system installation. The amount of water flow available on a consistent basis, since lack of rain can affect plant operation. Head, or the amount of drop between the intake and the exit. The more head, the more power that can be generated. There can be legal and regulatory issues, since most countries, cities, and states have regulations about water rights and easements.

                       for more information we recommend Wikipedia

    wikiHydroTimor -- on hydroelectric related terms -- by HydroTimor