Geothermal energy is thermal energy generated and stored in the Earth. It is a renewable source of energy that can be used to generate electricity or provide direct heat. There are three main types of geothermal power plants - dry steam, flash steam, and binary cycle plants. Geothermal reservoirs are found in areas with geysers, hot springs, volcanoes and high underground temperatures. While the initial investment is high, geothermal electricity generation costs can become competitive with other sources once plants are operational. India has potential geothermal reserves across its Himalayan regions and development is underway to establish the country's first geothermal plants.