Geothermal energy is heat derived within the sub-surface of the earth. Water and/or steam carry the geothermal energy to the Earth’s surface. Depending on its characteristics, geothermal energy can be used for heating and cooling purposes or be harnessed to generate clean electricity.
Geothermal energy is clean and is available 24 hours a day, 365 days a year. Geothermal power plants have average availabilities of 90 per cent or higher, compared with about 75 per cent for coal plants.
Indian geothermal provinces have potential to produce around 10,600 MW of power
About 340 hot spring localities have been identified; many of them have temperature nearing boiling point
These springs are located along the following 5 major regions namely NW-SE Himalayan arc system which is extended to Andaman Nicobar Island, Son-Narmada-Tapti lineament, West Coast continental margin along with its adjacent and surrounding areas, Gondwana grabens and Delhi fold regions
The top five countries in terms of geothermal power generation are the US, Philippines, Indonesia, Mexico and New Zealand
In India, the central government has been actively supporting research in geothermal energy for over two decades.
Systematic efforts to explore geothermal energy resources first commenced in India in 1973 and several promising sites were finalized. Some of these are Cambay Graben in Gujarat, Puga and Chhumathang in Jammu and Kashmir, Tattapani in Chhattisgarh, Manikaran in Himachal Pradesh, Ratnagiri in Maharashtra and Rajgir in Bihar
Oil and Natural GasCorporation (ONGC) will be implementing India’s maiden geothermal field development project in Ladakh
Also, Gujarat has already exploited geothermal power by digging shallow wells that generate about 20KW of electricity [which is used for captive consumption] in Dholera
Also, Gujarat became the first state in India to use geothermal energy to produce electricity
The exploration activities have revealed that, the Puga hot spring area, located at the junction of the Indian and Tibetan plates along the Indus Suture Zone, has the greatest potential for the near-term development of geothermal energy in the Indian subcontinent
It is said that the area exhibits vigorous geothermal activity in the form of hot springs, mud pools, sulphur and borax deposits. Also, It is estimated that more than 5,000 MWh of geothermal energy is available at Puga, which could be used for heating, for greenhouse cultivation and, eventually, to generate electricity
The limitations that have left the exploration of Geothermal energy in Nascent stages in India are:
High initial capital costs
It is suited for particular regions only. Even after finding, the drilling can be done only upto feasible depths
Geothermal heat coming from the reservoir below may die down or run out of steam even after years of activity, which results in more operational costs
Some studies indicate that they can be depleted, if the water is extracted faster than it can replenish itself. Hence, the sustainability issues
In some situations, geothermal energy sites are located farther from the population, thereby requiring a vast network of distribution This only adds up the overall cost of setting up a geothermal system
Environmental impacts of Geothermal Energy
Drilling and exploration [without thorough assessments] can cause habitat destruction and a lot of disturbance to wildlife, in a region
The high levels of seismicity of sensitive region adds to the need for detailed studies of the associated seismic risks
This is needed, as an earthquake, of magnitude 5.4, hit South Korea’s Pohang city, which is home to an experimental geothermal plant, in November 2017 and caused widespread destruction
