6. Energy Resources

Energy resources are essential for the sustenance of the human society as much as it is needed for the life and existence of an individual. Energy resources are of two kinds: renewable (solar, hydro-power, wind, tidal, biofuels) and the nonrenewable energy sources comprise coal, natural gas and petroleum, and nuclear raw materials. Geothermal energy is a continuous form of energy source. The world derives 2/3 of its produced energy from the fossil fuels and 1/3 from the nonfossil type, i.e., hydro-energy + nuclear energy. While the exhaustion of the nonrenewable energy sources is slated, that of the renewable variety appears inexhaustible. Coal (±lignite) provides 2/5 of the fossil fuels going for the production of electrical energy and there lies the main root of the global warming problem. Coal is a combustible sedimentary rock having both organic (C _org ≥ 50%) and inorganic components. Humic coal forms from different mixtures of macroscopic plant debris, whereas sapropelic coal forms from selected types of microscopic plants. Coalification: plant debris (biochemical changes) peat → (geochemical changes) → coal. Petrographic components: vitrain, clarain, durain, and fusain. Of the world’s total reserves of 848 Gt, India’s share is 284 Gt. However, it is generally high ash and noncoking. Bulk of India’s coals was deposited in Gondwana basins of Permo-carboniferous age. Add to these a proven reserve of 6.1 Gt of lignite in the Tertiary basins. Crude oil or petroleum is a mixture of hydrocarbons that remains liquid at atmospheric pressures. It is lighter than water. Chemically crude oil is made up of carbon (~85%), and hydrogen (13%) and the rest made up of S, O, N along with some trace metals. The constituent hydrocarbon molecules are alkanes, napthanes, and aromatic compounds including benzene. Oil and natural gas are produced from phytoplanktons deposited on water-sediment interface and modified by (bio-) geochemical and geochemical processes. Oil and gas formed at infinite number of points in the host rock and then migrated and accumulated in the low pressure zones (reservoirs). Although India identified 26 oilfields on its rightful areas, it produces about 1/3 of its requirements from its wells. India has a very good reserve of gas hydrates within its EEZ. After the WW II around the middle of the last century, the world saw the advent of another kind of fuel for energy (electrical) production. It was nuclear energy, accounting for about 16% of world energy today. In fact, it is the heat produced by fission of nuclei of suitable radioactive elements, such as U and Th that is utilized in heating water, creating steam that would rotate turbines and produce electricity. The positive thing about it is that the whole operation is “clean” and a plant runs for about 30–40 years with an initially high but later moderate cost. But two recent disasters in such plants, one at Chernobyl, Ukraine (1986) and the other at Fukushima, Japan (2011) have shaken the faith in this kind of energy source for many prospective users. Toward the end of 2014 India was having 20 nuclear power plants in operation in the country. India is at an enviable position with respect to the provision of Th resources in the form of monazite in the beach sands of Kerala, Tamil Nadu, and Odisha. But its own reserve of U ores is not encouraging. India’s main source of indigenous U ores lies in the Singhbhum Cu–U belt in eastern India. The Cuddapah basin in Andhra Pradesh is now showing promising potential in this respect.