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Hydropower (from Ancient Greek ὑδρο-, "water"), also known as water power or water energy, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the gravitational potential or kinetic energy of a water source to produce power. [1] Hydropower is a method of sustainable energy ...
Hydro turbines have a start-up time of the order of a few minutes. [37] Although battery power is quicker its capacity is tiny compared to hydro. [2] It takes less than 10 minutes to bring most hydro units from cold start-up to full load; this is quicker than nuclear and almost all fossil fuel power. [38]
A water power engine includes prime movers driven by water and which may be classified under three categories: [1]. Water pressure motors, having a piston and cylinder with inlet and outlet valves: their action is that analogous of a steam- or gas-engine with water as the working fluid – see water engine
Kaplan turbine and electrical generator cut-away view. The runner of the small water turbine. A water turbine is a rotary machine that converts kinetic energy and potential energy of water into mechanical work. Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now, they are ...
A wheel power divided by the initial jet power, is the turbine efficiency, η = 4u(V i − u)/V i 2. It is zero for u = 0 and for u = V i . As the equations indicate, when a real Pelton wheel is working close to maximum efficiency, the fluid flows off the wheel with very little residual velocity. [ 11 ]
In a thermal generating station, fuel is burned in a boiler to convert water to steam. The high-pressure steam is directed into a turbine that is connected to an electrical generator that produces electricity as it turns. A seawater condenser is used for cooling the spent steam from the turbine, converting it back to water that is reused in the ...
The hot exhaust gas from an MHD generator can heat the boilers of a steam power plant, increasing overall efficiency. Practical MHD generators have been developed for fossil fuels, but these were overtaken by less expensive combined cycles in which the exhaust of a gas turbine or molten carbonate fuel cell heats steam to power a steam turbine.
A screw turbine (also known as an Archimedean turbine, Archimedes screw generator or ASG, or Archimedes screw turbine or AST) is a water turbine that converts the potential energy of water on an upstream level into work. This hydropower converter is driven by the weight of water, similar to water wheels, and can be considered as a quasi-static ...