GENERAL ARTICLES CURRENT SCIENCE, VOL. 95, NO. 7, 10 OCTOBER 2008 846 The authors are in the Department of Botany and Microbiology, Post Box 22, H.N.B. Garhwal University, Srinagar-Garhwal 246 174, India. *For correspondence. (e-mail: kailash0011@rediffmail.com) Geothermal energy resource utilization: Perspectives of the Uttarakhand Himalaya Kailash N. Bhardwaj* and S. C. Tiwari The developing world community is struggling with scarcity of power. Most of its power is derived from non-renewable conventional energy resources which are decreasing day by day. Therefore, presently renewable energy resource utilization is the best solution to combat this problem. Geother- mal energy is one such renewable energy resource which is still unexplored. Besides, there are other potential applications of this energy resource waiting to be explored. It is second to none in its ap- plicability and environment-friendly aspects when compared to other contemporary energy re- sources. In the present article, attempts have been made to describe the multi-dimensional utilization of geothermal energy resource as far as India or in particular, the Uttarakhand Himalaya is con- cerned. This remote region is India’s most promising geothermal province. The present energy sce- nario in India needs special attention to explore geothermal energy. Keywords: Geothermal energy, renewable energy resources, utilization. TODAY, most of our energy is drawn from conventional non-renewable energy resources, i.e. coal, biomass and petroleum products. At present, coal alone accounts for about 70% of India’s electricity supply 1 , but it is not en- vironment-friendly. The main culprit behind conventional non-renewable energy resources is the uncontrolled emis- sion of CO 2 which leads to global climate change. Re- cently, on the topic of global climate change 2 , the G8 leaders agreed on the need for the world to cut carbon emissions by at least 50% by 2050. Environmental acti- vists and leaders from the developing countries called it a ‘toothless gesture’. Blind use of coal, biomass and petro- chemicals leads to greater pressure on the earth’s carrying capacity. Efforts are on in this respect; priorities are being given to such alternative options which are environment- friendly, economically viable, renewable and have vast practical functions. One such deserving and potential but quite unrecognized energy resource in India is geothermal energy, which needs to be explored for our common energy requirement. It is a clean energy source as it does not emit carbon or produce other harmful by-products. Exten- sive research in this respect showed it as having a good prospect for energy security with outstanding long-term potential 3 . The Geological Survey of India (GSI) in collaboration with UN organization explored 4 the geothermal provinces of India in the 1970s. The Himalayan province among others, constitutes high-temperature geothermal springs. Uttarakhand Himalaya is part of the Central Indian Hima- laya which is endowed with a vast majority of geothermal springs, which contain medium to high enthalpy water that could prove to be a potential resource for various applica- tions. Keeping the Uttarakhand Himalayan region in view, the present article sheds light on geothermal resource utilization, its availability and future prospects. Geothermal: The untamed energy resource Geothermal (Greek: geo means earth and therme means heat) energy is the heat within the earth. This energy can be used to produce electricity, to heat buildings and to provide hot water for various purposes. There exists a considerable temperature gradient inside the earth which is found to be quite high in some geographical locations. Deep subterranean faults and cracks allow rainwater and snowmelt to seep underground. This water is heated by the hot rock and forms a geothermal reservoir beneath the earth. It circulates back up to the earth’s surface and forms geothermal springs, geysers or fumaroles. Beside the natural geothermal springs, artificial ones can also be made by exploratory drilling. It is a common approach to search for geothermal gradients and reservoirs where natural geothermal springs are not found. High-tempe- rature gradient exists in certain geographic locations on the earth, i.e. Ring of Fire area which surrounds the Pacific Ocean. India has about 400 medium to high-enthalpy geothermal springs, clustered in seven provinces. The most promising provinces are the Himalaya, Sohana, Camby, Son–Narmada–Tapi (SONATA) and the Goda-