Definition of Hydro-electric

Although large hydroelectric installations generate most of the world's hydroelectricity, small hydro schemes are particularly popular in China, which has over 50% of world small hydro capacity.

Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, and operation of various machines, such as watermills, textile machines, and sawmills. The energy of moving water has been exploited for millennia. In India, water wheels and watermills were built; in Imperial Rome, water powered mills produced flour from grain, and in China and the rest of the Far East, hydraulically operated "pot wheel" pumps that raised water into irrigation canals. In the 1830s, at the peak of the canal-building era, hydropower was used to transport barge traffic up and down steep hills using inclined plane railroads. Direct mechanical power transmission required that industries using hydropower had to locate near the waterfall. For example, during the last half of the 19th century, many grist mills were built at Saint Anthony Falls, utilizing the 50 foot (15 metre) drop in the Mississippi River. The mills contributed to the growth of  Minneapolis. Today the largest use of hydropower is for electric power generation, which allows low cost energy to be used at long distances from the water source.