Geothermal energy is an energy source that is stored in the form of heat beneath the earth's surface, which is clean, renewable, sustainable, carbon free, continuous, uninterrupted and environment-friendly. It is the only renewable energy available 24x7 to the mankind not requiring storage and unaffected by day-night or seasonality variance. India has seven geothermal provinces and a number of geothermal springs. Geothermal resources in India have been mapped by Geological Survey of India (GSI) and broad estimate suggests that there could be 10 GW geothermal power potential as per Ministry of New and Renewable Energy (MNRE).
Ladakh region of India is endowed with some of the best geothermal prospects in the country. Puga and Chumathang in Eastern Ladakh happen to be the most promising geothermal fields in the country. Initial exploratory efforts in these areas were made in 1970-80s by GSI. But development efforts to exploit geothermal energy by government as well as private agencies did not materialize for various reasons. Subsequently, efforts were taken up by ONGC Energy Centre (OEC) for harnessing geothermal energy at Puga and Chumathang geothermal sites of Ladakh and MoU for the same was signed with UT Administration of Ladakh and Ladakh Autonomous Hill Development Council, Leh on 06.02.2021 at Leh. It can be considered as the first step towards achieving the goal of creating Carbon Neutral Ladakh which was a clarion call by Hon’ble Prime Minister of India on Independence Day 2020. This project of OEC is a first step towards putting India on Geothermal map of the World to generate Geothermal Power. Further, direct heat energy applications make it most relevant to Ladakh.
Apart from harnessing geothermal energy at Ladakh, efforts are also being made to utilize geothermal energy from the existing Oil & Gas wells in Gandhar oil field of ONGC Ankleshwar Asset, Gujarat. Cambay Basin would be the next region that OEC would be targeting. This region has several existing inventory of abandoned wells which are non-flowing for oil and gas but has the Rocks/Sands that have sufficient thickness, porosity and permeability with large fluid flow rates at moderate temperatures and with capacity to sustain the heat for at least 25 years. The moderate temperature ranges are sufficient to run power plant based on Organic Rankine Cycle (ORC). Hence, OEC is working to utilize the appropriate depleted oil/ gas fields/ wells for geothermal exploitation.