I want to know about HYDRO energy. 1. How it works? 2. How much supply? 3. Problems with HYDRO energy?

What is hydro energy has been made clear enough in previous two answers. So I will now write about how hydro power is generated, and some problem with hydro energy.

Hydro power is generated by directing water flowing with high speed, or under great pressure, or a combination to the inlet of a water turbine. This flow of water makes the water turbine rotate with great force and speed, converting the kinetic energy water velocity, and potential energy of water pressure in to mechanical energy delivered to the shaft of the turbine. The turbine shaft is directly coupled to a generator. The mechanical energy produced by the turbine is thus used to drive the generator which produces electrical power.

The water for generation of hydro-power is provided by rivers, which flow from places of high altitudes to places of low altitude. In this way the river water possesses potential energy that gets converted to kinetic energy as it flows down its course. To use maximum of the the potential energy of water that it possesses while it is at higher altitudes, the water may be directed from high altitudes to power generating stations located at much lower altitudes through artificially built ducts. Also the river water may be collected at higher altitudes in dams so that it can be used for generation of energy as required, rather than depending on natural inflow of water.

Cost of all these facilities increases the cost of construction of hydro power station much more than that of thermal power station of comparable generating capacity. However operating power of hydro power stations is less than that of thermal power station.

In spite of the heavy investment in constructing dams, it is usually not economically possible to make hydro power station that generate electric power at full capacity round the year. Therefore, capacity of hydro-power station is more likely to be used to meet additional peak requirements of power rather than the stable base requirements, 24 hours a day.

Apart form high capital cost and dependence on fluctuating and some times uncertain water flow, the major disadvantage of hydro power is that the such power stations have to be located where the water is available rather than where the electricity is required. Also the potential of generating hydro power by way of availability of water resources is limited as compared to availability of coal for thermal power stations.