Hydroelectricity

A hydroelectric dam and plant on the Muskegon river in MichiganMain article: Hydroelectricity
Hydroelectric dams impound a reservoir of water and release it through one or more water turbines to generate electricity.


[edit] Pumped storage
A pumped storage hydroelectric power plant is a net consumer of energy but decreases the price of electricity. Water is pumped to a high reservoir during the night when the demand, and price, for electricity is low. During hours of peak demand, when the price of electricity is high, the stored water is released to produce electric power.


[edit] Solar
Main article: Solar power

A control room of a waste incineration power plantA solar photovoltaic power plant converts sunlight into electrical energy, which may need conversion to alternating current for transmission to users. This type of plant does not use rotating machines for energy conversion. Solar thermal electric plants are another type of solar power plant. They direct sunlight using either parabolic troughs or heliostats. Parabolic troughs direct sunlight onto a pipe containing a heat transfer fluid, such as oil, which is then used to boil water, which turns the generator. The central tower type of power plant uses hundreds or thousands of mirrors, depending on size, to direct sunlight onto a receiver on top of a tower. Again, the heat is used to produce steam to turn turbines. There is yet another type of solar thermal electric plant. The sunlight strikes the bottom of the pond, warming the lowest layer which is prevented from rising by a salt gradient. A Rankine cycle engine exploits the temperature difference in the layers to produce electricity. Not many solar thermal electric plants have been built. Most of them can be found in the Mojave Desert, although Sandia National Laboratory, Israel and Spain have also built a few plants.


[edit] Wind
Main article: Wind power

Wind turbine in front of a thermal power station in Amsterdam, NetherlandsWind turbines can be used to generate electricity in areas with strong, steady winds. Many different designs have been used in the past, but almost all modern turbines being produced today use a three-bladed, upwind design. Grid-connected wind turbines now being built are much larger than the units installed during the 1970s, and so produce power more cheaply and reliably than earlier models. With larger turbines (on the order of one megawatt), the blades move more slowly than older, smaller, units, which makes them less visually distracting and safer for airborne animals. However, the old turbines can still be seen at some wind farms, particularly at Altamont Pass and Tehachapi Pass.


[edit] Operations
The power station operator has several duties in the electrical generating facility. Operators are responsible for the safety of the work crews that frequently do repairs on the mechanical and electrical equipment. They maintain the equipment with periodic inspections and logs temperatures, pressures and other important information on regular intervals. Operators are responsible for starting and stopping the generators depending on need. They are able to synchronize and adjust the voltage output of the added generation with the running electrical system without upsetting the system. They must know the electrical and mechanical systems in order to troubleshoot problems in the facility and add to the reliability of the facility. Operators must be able to respond to an emergency and know the procedures in place to deal with it.