Definition of Hydropower

Hydropower or 'water power' can be defined as the potential energy contained in water at a height. Water constantly moves through a vast global cycle, evaporating from lakes and oceans, forming clouds, precipitating as rain or snow, then falling back to the ocean. The energy of this cycle can be tapped to produce electricity or for mechanical tasks like grinding grain. One third of the solar radiation reaching the Earth is responsible for running of the hydrologic cycle. Therefore, the energy of water never fails to be replenished. Because the hydrologic cycle is a never ending system, hydropower is considered a renewable energy. Indeed, it is the largest renewable resource used for electricity generation.

Classification of Hydroelectric Powerhouses

1. Big Scale Hydroelectric Systems
Power of big scale system is 50 MW and over. 50 MW can light or is equal to 500.000 unit of 100 watt electric bulbs. In other words, if we assume that 5Kw electrical power required for a house, big scale powerhouses can meet the need of 10.000 houses. Electricity produced can be distributed with the energy lines to the other regions of the country.

2. Small Scale Hydroelectric Systems 
 Hydroelectric system which produces electricity between 10 to 50 MW is defined as small scale hydroelectric system. It can both connected to national grid system and use to power a town or large factories. We can say that 10 MW power is enough for a town with a population of 10000 citizens.

3. Mini Scale Hydroelectric Systems 
Hydroelectric systems which has power between 101 Kw to 10,000 Kw are called mini scale hydroelectric systems. These systems contributes to the national grid systems less then those explained above. These are usually designed and build for small settlements near a river. A 100 Kw hydroelectric turbine can supply energy needs of 20 houses.

4. Micro Scale Hydroelectric Systems 
These are the smallest hydroelectric systems and do not contribute to the national grid system. These are convenient for settlements which is located far from the main settlement areas. Their power usually just enough to power a home or a farm.

History of Hydropower

People have been benefiting from the power of water for more than two thousand years starting with the wooden waterwheel. Water wheels were used to grind wheat into flour as early as 100 B.C in many parts of Asia mostly for milling grain. Improved engineering skills during the 19th century, combined with the need to generate electricity, modern-day turbines gradually replaced the water wheel and soil and rock dams were built to control the flow of water and produce electricity. The golden age of hydropower started at the beginning of the 20th century before oil took the lead in energy generation. Europe and North America built large hydropower plants, equipment suppliers spread to supply this thriving business.