1. Hydro power generation
This is traditional method of producing cheap electricity but involve some problems
I. The people living in these areas where the dams to be constructed are shifted to some other places.
II. In winter, its capacity decreases due to shortage of water.
III. Water table near a dam rises due to which water logging occurs and the land becomes uncultivated.
2. Thermal power generation
I. This method involves burning of fossil fuels (Oil, gas, Coal). These are non-renewable sources.
II. Fossil fuels releases smoke and other harmful gases in atmosphere.
3. Solar power generation
I. Very high installation cost
II. Not applicable for night
III. Number of batteries required