What is the rating of the hydro-generators?

Hydro-generators, used in hydroelectric plants to convert the energy of flowing water into electricity, vary widely in their power output ratings. These ratings can range from a few kilowatts for small, micro-hydro installations to several gigawatts for the largest power plants in the world.

For example, conventional hydroelectric generators at small to medium-sized plants may have ratings from a few megawatts (MW) up to several hundred MW. Large hydroelectric facilities, such as those at major dams, can have individual generator units rated at up to 800 MW or more. The Three Gorges Dam in China, one of the world’s largest hydroelectric power stations, has 32 main generators, each with a capacity of 700 MW, and two plant power generators, each with 50 MW, giving a total capacity of 22,500 MW.

These ratings are determined by factors including the flow rate of water, the height from which the water falls (head), and the design efficiency of the turbine and generator set. A higher water flow and greater head result in more energy that can be converted into electricity, requiring a generator with a larger rating to handle the output.