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Hydropower is now used principally for hydroelectric power generation, and is also applied as one half of an energy storage system known as pumped-storage hydroelectricity. Hydropower is an attractive alternative to fossil fuels as it does not directly produce carbon dioxide or other atmospheric pollutants and it provides a relatively ...
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. A PSH system stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off ...
The net capacity factor is the unitless ratio of actual electrical energy output over a given period of time to the theoretical maximum electrical energy output over that period. [1] The theoretical maximum energy output of a given installation is defined as that due to its continuous operation at full nameplate capacity over the relevant period.
Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical , electric power , mechanical work , light (radiation), or heat .
In a conventional thermal power plant, like a coal-fired power station or nuclear power plant, the energy created by the chemical or nuclear reactions is absorbed in a working fluid, usually water. In a coal plant, for instance, the coal burns in an open chamber which is surrounded by tubes carrying water.
The higher the heat rate (i.e. the more energy input that is required to produce one unit of electric output), the lower the efficiency of the power plant. The U.S. Energy Information Administration gives a general explanation for how to translate a heat rate value into a power plant's efficiency value. [4] Most power plants have a target or ...
Low-head hydro power refers to the development of hydroelectric power where the head is typically less than 20 metres, although precise definitions vary. [1] Head is the vertical height measured between the hydro intake water level and the water level at the point of discharge.
Thus, "impulse" energy does work on the turbine. Maximum power and efficiency are achieved when the velocity of the water jet is twice the velocity of the rotating buckets, which, assuming that water jet collides elastically with the bucket, would mean the water leaves the bucket with zero velocity, thus imparting all kinetic energy to the wheel.