Oil and Natural Gas Corporation (ONGC) has started drilling to discover energy from the bowels of the earth in Puga Valley in Ladakh – an area which lies on the Himalayan geothermal belt.
- ONGC started drilling at the remote valley located at an altitude of 14,000 feet and has hit upon high pressure steam at 100o Celsius with a discharge of 100 tonne geothermal energy per hour.
- The reassured crew is now speeding ahead with the first phase of its geothermal project.
- On February 7, 2021, an agreement for establishing the first geothermal Power Project was announced. Ladakh’s Puga valley was the natural choice. The power plant here will be not only India’s first one but also the highest.
About Geothermal Energy
- Geothermal Energy is a mature renewable energy technology that has a potential to provide clean and reliable energy for power generation heating/cooling.
- Geothermal Energy can be utilized for both electric power production and direct heat applications including Ground Source Heat Pump (GSHP) for space or district heating, generating hot water for domestic/ industrial use, running cold storages and greenhouse, horticulture, etc.
- However, Geothermal Energy has experienced modest growth worldwide in recent times as compared to other RE sources especially wind or solar due to its site specific nature, risk/uncertainty involved with resource exploration and high capital cost.
- Total Installed Capacity for Geothermal Power is around 13.5 GW. Leading countries in geothermal power generation capacity are USA (3600 MW), Philippines (1900 MW), Indonesia (1600 MW), New Zealand (1000 MW).
India and Geothermal Energy
- India is still at nascent stage of geothermal energy utilization with no geothermal power plant set up in the country so far due to high upfront cost of Rs 30 Cr/ MW & indicative Tariff in range of Rs 10 per KWh, site specific deployment, lack of load center and power evacuation facility nearby, high risk involved in exploration, etc.
- Geological Survey of India (GSI) with CSIR – National Geophysical Research Institute (NGRI) carried out preliminary resource assessment for the exploration and utilization of geothermal resources in 1970s & 1980s in the country.
- As per preliminary investigations undertaken by the GSI, there are around 300 geothermal hot springs in India.
The promising geothermal sites for electric power generation are:
Puga Valley & Chummathang in Ladakh,
- Cambay in Gujarat,
- Tattapani in Chattisgarh,
- Khammam in Telangana &
- Ratnagiri in Maharasthra.
- The promising geothermal sites for direct heat use applications are Rajgir in Bihar, Manikaran in Himachal Pradesh, Surajkund in Jharkhand, , Tapoban in Uttarakhand & Sohana region in Haryana.
Geothermal use technologies
Hot water and steam from deep underground can be piped through underground wells and used to generate electricity in a power plant. There are three types of geothermal power plants:
- Dry Steam Plants which use geothermal steam directly. Dry steam power plants use very hot (>235 °C) steam from the geothermal reservoir. The steam goes directly through a pipe to a turbine to spin a generator that produces electricity.
- Flash Steam Plants which use high pressure hot water to produce steam. Flash steam power plants use hot water (>182 ºC) from the geothermal reservoir. When the water is pumped to the generator, it is released from the pressure of the deep reservoir. The sudden drop in pressure causes some of the water to vaporize to steam, which spins a turbine to generate electricity. Hot water not flashed into steam is returned to the geothermal reservoir through injection wells.
- Binary Cycle Plants which use moderate-temperature water (107 to 182 ºC) from the geothermal reservoir. In binary systems, hot geothermal fluids are passed through one side of a heat exchanger to heat a working fluid in a separate adjacent pipe. The working fluid, usually an organic compound with a low boiling point such as Iso-butane or Iso-pentane, is vaporized and passed through a turbine to generate electricity.
(Sources: TOI and Yojana)
