Oil and Natural Gas Corporation (ONGC) has signed a memorandum of understanding (MoU) with the Union Territory (UT) of Ladakh and Ladakh Autonomous Hill Development Council (LAHDC), Leh, to develop India's first geothermal field development project. ONGC told media sources that the MoU has been signed as a step towards creating a carbon-neutral Ladakh. The firm said geothermal resource development could revolutionise farming in Ladakh, which is currently dependent for supply of fresh vegetables, fruits from outside the UT, round the year. ONGC has planned this field development in Ladakh in three phases. Phase one involves exploratory-cum-production drilling of wells, up to 500 m deep and setting up a pilot plant of up to 1 MW power capacity. Phase two would involve a deeper and lateral exploration of a geothermal reservoir by drilling an optimal number of wells and setting up a higher capacity demo plant and preparing a Detailed Project Report. Phase three would involve commercial development of the geothermal plant. ONGC said that Puga and Chumathang in Eastern Ladakh, discovered in the 1970s, happens to be the most promising geothermal fields in India.Make in Steel 202124 February Click for event info4th Indian Cement Review Conference 202117-18 March Click for event info What are geothermal fields? Geothermal fields develop when water from the earth's surface is able to seep through faults and cracks within rocks, sometimes to depths of several kilometres, to reach hot regions within the crust. When the water is heated, it rises back naturally towards the surface by the process of convection and may appear there again in the form of geysers, hot springs, fumaroles or hot mud holes. These are common along tectonic plate boundaries. Geothermal fields are usually developed in stages. During the preliminary stage, at least one single-flash unit is built and operated. During the later stage, a double-flash unit is integrated with the single-flash unit. The integration occurs through the use of the separated liquid from the single-flash unit as the source of low-pressure flash steam (at two pressure levels) for the double-flash unit. The double-flash unit's addition raises the thermodynamic utilisation efficiency of the entire plant since more power is generated with the same amount of geofluid. There are seven geothermal provinces in India: the Himalayas, Sohana, West coast, Cambay, Son-Narmada-Tapi basins, Godavari, and Mahanadi. Image: Geothermal resource development could revolutionise farming in Ladakh. (Representational image only.)Also read: Hydropower projects on Indus, Ladakh cleared