EXPLOITATION OF ENERGY RESOURCES
Conventional Sources of Energy
1. Coal
Coal is one of the most important sources of energy. Most of the coal, which is obtained today, is from underground mines of different types depending on their distance from the Earth’s surface. Coal comprises three-fourth of the total fossil fuels of the world. India has large proven resources and still larger geological reserves. India ranks third in terms of world production of coal. In India, there would be enough coal for more than 100 years, however, it is concentrated largely in the eastern and central parts of the country.
2. Oil and Natural Gas
In India, efforts made by the Oil and Natural Gas Corporation (ONGC and Oil India since the late 1950s have led to the identification of a number of oil and gas deposits both offshore and onshore. The onshore fields were mainly discovered in the Mumbai. Gujarat, Assam and Arunachal Pradesh; and the offshore fields in the sea were notably the Mumbai High fields such as North and South Basin and South Tapti. Oil and gas has also been discovered in the Godavari Basin and on the East Coast. The new exploration strategy developed during the first two years of Seventh Plan places emphasis on intensive exploration survey and drilling in order to add to petroleum reserves and to augment production as early as possible.
Natural gas is emerging as an important source in India’s commercial energy scene in view of large reserves of gas that have been established in the country. In view of growing importance of natural gas in the country, the Gas Authority of India Limited (GAIL), a wholly-owned Government of India undertaking, was established in 19841The main objective of the company are processing, marketing, transportation and distribution of natural gas in all its forms.
3. Hydro Energy
Hydro energy can also be considered as an indirect source of solar energy. The potential energy of water stored at a height is converted into mechanical and electrical energy as this water falls and drives turbines and electric generators.Today, about 23 per cent of the total electric power in the world comes from hydro power. The total hydro-electric potential in India has been estimated at about 472x 109 kilowatt hours or 472 terrawatt hours normally. But, we have exploited only a little more than 16 per cent of the total potential.
Electrical energy generation by hydro-electric power plants is not polluting and uses a renewable source of energy. However, there are several problems associated with the construction of giant dams on natural waterways. The construction of such dams alter the downstream ecology as well as that in the lake area behind the dam. Huge areas get submerged, and flora and fauna or any agricultural produce of this land get affected. People and towns in this area have to be removed and relocated, causing disturbance and sometimes hardship. Again, the time taken for such larger schemes to fructify is usually quite long. For these reasons, emphasis is now being given to supplement such large projects with small size hydro projects called mini-hydro or micro-hydel projects which can be built on small streams and even on canals, without large dams.
4. Tidal Energy
Tides are created by the combined gravitational effect of the Earth, the Moon and the Sun. Though the tide is the universal phenomenon of the Earth’s sea-water body, some regions are more favourable for the establishment of such power plant for the commercial production of tidal energy. Primary requirements for the construction of an installation having a capacity over 200 MW, are
(i) an average tide of 5-12 metres;
(ii) the possibility of linkage to a grid in order to accommodate the variable power
(iii) favourable geographical location and favourable socio-economic and ecological conditions. Bulb type turbines as used in conventional hydro-electric stations have proved to be reliable for generating power from the tides.
In India, three potential sites have so far been Identified, namely, the Gulfs of Kutch and Cambay on the west coast in Gujarat and the Sundarbans along the east coast in West Bengal.
5. Geothermal Energy
Geothermal energy is the exploitation of heat energy of Earth within the 10 km of the Earth’s upper crust. Geothermal energy can be processed for generation of power, where the geothermal fluid has a temperature of 130 degree C. Geothermal manifestations are widespread in India in the form of 340 Hot Springs localities. Only a few direct utilization schemes have been launched by various agencies. They are in Puga, Chhumuthang (Leh District), Manikaran and Bakreshwar ( West Bengal). Of these, India’s most promising geothermal field is in in Puga va11ey in Laddakh. Tatapani in Himachal Pradesh is another promising geothermal area in India.
6. Bio-energy .
Bio-energy includes those processes where biological forms of matter, such as plants, vegetables, enzymes etc. provide the basis for energy for its conversion from one form to another form of energy. The widest use of bio energy is in the traditional ways, where wood, plants and agricultural matter are directly burnt to provide heat.
Biogas
Biogas means a gas produced by the anaerobic digestion or fermentation of organic matter. The organic matter can be manure, sewage sludge, municipal solid waste, biodegradable waste or any other biodegradable feedstock. Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of hydrogen sulfide (H2S), moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat.
Biomass
Biomass covers a wide range of materials, encompassing all kind of animal, organic and synthetic wastes and a special variety of vegetation-wild grass, shrubs and some plants and tress, especially cultivates to derive energy. The major components of biomass are mainly carbohydrates-sugars, starches and cellulose-with variable nitrogen an phosphorous contents. There are three basic systems for conversion of biomass into energy resources.
(a) Combustion Pyrolysis – Chemical decompose l 0n oil (methanol) and charcoal.
(b) Biogasification – Anaerobic digestion of biomass to produce combustible gas (biogas) comprising of methane, hydrogen.
(c) Fermentation – Conversion of sugar and starch into alcohol to produce ethanol and solid residual fuel.
Non-Conventional Sources
1. Solar Energy
Solar radiant energy falling on the surface of the Earth in the form of visible lights can be converted into thermal energy. The heat generated in a solar collector can be utilized for variety of applications such as cooking of food, heating of water, drying of food grains and vegetables, wood seasoning, desalination of water, generation of mechanical and electrical power etc.
2. Wind Energy
Wind energy is the kinetic energy associated with movement of large masses of air resulting from the differential heating of the atmosphere by the Sun. Hence wind energy is nothing but converted form of solar energy. It is estimated that about 106 to 107 MW of usable power is continuously available in the Earth’s winds. Though the total quantity of this resource is extrememly large, it is concentrated in certain regions, and can vary a great deal with time at given location. For the utilization of wind energy, the speed of wind must be between 8 to 22m per second. Wind energy is renewable and posses no major environmental threats.
3. Ocean Energy
The sea, which is constantly receiving solar radiations and act as the world’s largest natural solar collector, has potential to provide a means of utilizing renewable energy. It acts not only as collector, but also has an enormous storage capacity. Energy from the ocean is available in several forms such as ocean thermal energy, wave energy, tidal energy, salinity gradients, ocean currents, ocean winds and bio-mass.
4. Wave Energy
Movement of large quantities of water up and down can, in principle, be harnessed to convert it into usable form of energy, such as, electricity or mechanical power. Several types based on flats, flaps, ramps and oscillating air water columns have been worked UpOl1 to harness wave energy. It is more reliable than the wind energy because here the fluctuation is less than the wind. However at present, due to infant stage of its technology, the cost per unit of energy converted is high because of the need for special structures at sea, corrosion problem associated with the use of sea water and the problem of transmitting the power onshore.
The tropical coastline of India, especially south-west coastline, is very suitable for establishing such energy plants. Department of Ocean Development has estimated the wave energy potential in India about 40,000 MW. Ocean Energy Cell has established a pilot power plant at Vizhinjam (Kerala), of 120
MW capacity during monsoon period and 30 MW during non-monsoon period. OEC is also develop- ing five other similar plants at Thangaserry in Kerala.
5. Nuclear Energy
Nuclear energy can be obtained both through fusion and the fission processes. Enormous amounts of energy is released from small quantity of fuel in both these processes, e.g., if one tonne of Uranium is totally fissional, it can theoretically yield energy equivalent to about 3 million tonnes of coal.
Nuclear Reactor
The nuclear reactor or atomic reactor is a kind of furnace for carrying out the controlled fission of a radioactive material like Uranium-235 for producing atomic power. It’s in the reactor that the heat energy is produced from fission reactions, which is then taken out and converted into electricity. Thus, it’s an assembly in which nuclear fission chain reaction is maintained and controlled for producing nuclear energy, radioactive nuclides or artificial elements. In order that reaction should not get out of control.it is regulated by neutron absorbers – the control rods made of graphite or beryllium, which allow only sufficient free neutrons to exist in reactor core to maintain the reaction at constant level.
Nuclear Fuel
The fissionable material used in nuclear reactors for producing energy by the fission process is called a nuclear fuel. The fuel used in nuclear power plants is enriched uranium-235 isotope. The remaining being U-238 isotope, which does not get fissioned easily. The natural uranium, which contains a very low percentage of U-235 in it. Thus the natural uranium cannot sustain or maintain a nuclear chain reaction. Since naturally occurring uranium has very little U-235, so it has first to be processed to increase the percentage of fissionable U-235 in it. This process is called enrich- ment of uranium and uranium, thus obtained, is called enriched uranium.
Even the enriched uranium used in reactors contains both type of atoms – U-238 and U-235. But, it’s the U-235 atoms, wh~ch act as real fuel and are used in the reactors in the form of long rods or strips, called fuel.
6. Atomic Energy
The prime objective of the atomic energy programmes as defined in the Atomic Enrrgy 74.ct of 1948, are the development, control and use of atomic energy solely for peaceful purposes, namely, the generation of electricity and ,the development of nuclear applications in research, agriculture, indus- try, medicine and other areas. To achieve this objective, Tata Institute of Fundamental Research (TIFR) and Bhabha Atomic Research Centre (BARC) were established in 1945 and 1967, respectably as the grass root Research Institution which is catering the ‘diverse programmes related to research and training. Besides these, there are a number of research, training institutions and department which are involved in exposing its new dimensions.
The Atomic Energy Commission, set up in 1948, is responsible for formulating the policy for all atomic energy activities in the country. The Department of Atomic Energy (DAE), set up in 1954, is the executive agency for implementing the atomic energy programme.
The Nuclear Power Corporation of DAE is responsible for design, construction and operation of nuclear powere stations. Nuclera Power Corporation is at present operating the nuclear power stations: Tarapur Plant (2X220 MW), Trombay Plant (2X220 MW), Kalpakkam Plant (2X235 MW), Kaiga Plant (2X 235 MW).
