Oil and Gas Conservation and Its Relevance in Daily Life

SOURCES OF ENERGY
Energy can neither be created nor destroyed. Energy can only be converted from one form to another. E.g. if we drop a plate from a height, the potential energy of the plate gets converted mostly to sound energy when it hits the ground, chemical energy in the wax is converted to heat energy & light energy on burning.
The total energy during a physical or chemical process remains the same. In the above examples, energy in the usable form is dissipated to the surroundings in less usable forms. Hence, any source of energy we use, to do work, is consumed & can not be used again.
CLASSIFICATION OF SOURCES OF ENERGY:
The sources of energy are usually classified either as: 1. Renewable and Non-renewable source of energy. 2. Conventional & Non-conventional source of energy. Renewable sources of energy: • Renewable sources of energy are those which are inexhaustible i.e. which can be replaced as we use them & can be used to produce energy again & again. • These are available in an unlimited amount in nature & develop within a relatively short period of time. • E.g. solar energy, wind energy, water energy, geothermal energy, ocean energy, biomass energy (We can get a continuous supply of biomass only if we plant trees in a planned manner. In case, it is not done so, we would fall short of biomass), nuclear energy (Nuclear energy is also inexhaustible as only small mass of uranium produces large amount of energy, e.g. one atom of uranium produces 10 million times the energy produced by the combustion of an atom of carbon from coal.) Non Renewable sources of energy: • Non renewable sources of energy are those which are exhaustible & can not be replaced once they have been used. • These sources have been accumulated in nature over a very longer period of million of years. • E.g. fossil fuel like coal, petroleum, natural gas. Conventional source of energy: • Conventional sources for energy are those which are used extensively & meet a major portion of our energy requirement. • e.g. fossil fuel (coal, petroleum, natural gas), hydro-energy. • Conventional sources also include biomass energy & wind energy as these are also used from ancient times. Non Conventional sources of energy: • Non conventional sources of energy are those which are not used as extensively as the conventional ones. These partially meet our energy requirements. • Solar energy, ocean energy (tidal energy, wave energy, ocean thermal energy), geothermal energy & nuclear energy belong to this category. These sources of energy which have been tapped with the help of advanced in technology to meet our growing energy needs are also called alternative sources of energy.

FOSSILS FUEL: The fuels which are obtained from the remains of plants & animals are called fossil fuels. E.g. coal, petroleum, natural gas.
The remains of plants & animals which got buried inside the earth million of years ago, changed into coal, petroleum & natural gas due to excessive heat & high pressure inside the earth. • The coal as a source of energy made the industrial revolution possible. • Fossil fuels is a major fuels used for generating electricity, in gas stoves & for running vehicles. • The growing demand for energy is largely met by fossil fuels-coal & petroleum. • There are only limited reserves of fossil fuels. The fossil fuels are non-renewable sources of energy. So we need to conserve them. If we continue consuming these fossil fuels at such alarming rates, petroleum will be finished in next 40 years & coal in next 100 years. In order to avoid this, alternate sources of energy were explored. Disadvantages of using fossil fuel: (i) Burning of coal & petroleum lead to air pollution. The oxides of carbon, nitrogen & sulphur that are released on burning fossil fuels are acidic oxides. These lead to acid rain which affects our water & soil resources. (ii) Carbon di oxide released during burning of fossil fuels are also causing green house effect.
However, the pollution caused by burning fossil fuels can be somewhat reduced by increasing the efficiency of the combustion process & using various techniques to reduce the escape of harmful gases & ashes into the surroundings.
THERMAL POWER PLANT: • Large amount of fossil fuels are burnt every day in power stations to heat up water to produce steam. This steam is made to fall on the turbine blades thereby rotating the turbine which in turn rotates the armature of the generator producing electricity. • The transmission of electricity is more efficient than transporting coal or petroleum over the same distance. Therefore, many thermal plants are set up near coal or oil fields. • The term ‘thermal power plant’ is used since fuel is burnt to produce heat energy which is converted to electricity.
HYDRO POWER PLANTS: • Hydro power plants convert the potential energy of falling water into electricity. • Since there are very few water-falls which could be used as a source of potential energy therefore dams are made to collect water in large quantity. • Quarter of our energy requirement is met by hydro power plants. • In order to produce hydel electricity, high rise dams are constructed on the river to collect water in large reservoirs. The kinetic energy of moving water gets converted into potential energy of water when water level rises in the reservoir. The water from the high level in the dam is carried through pipes to the turbine, at the bottom of the dam. This moving water rotates turbine thereby producing electricity. • Hydro power is a renewable source of energy since the water in the reservoir would be refilled each time it rains. Disadvantage of Hydro Power Plants / Dams: 1 The dams can be constructed only in limited number of places, preferably in hilly regions. 2 Large areas of agricultural land & human habitation are to be sacrificed as they get submerged. 3 Large eco-systems are destroyed as they get submerged. 4 The vegetation which is submerged rots under anaerobic conditions & gives rise to large amounts of methane which is also a green house gas. 5 It creates the problem of satisfactory rehabilitation of displaced people • Opposition to the construction of Tehri dam on the river Ganga and Sardar Sarovar project on the river Narmada are due to above problems.
WIND ENERGY: • Unequal heating of the landmass & water bodies by solar energy generates air movement & causes wind to blow. • The kinetic energy of the wind can be used to do work. This k.E was harnessed by the wind mills to do mechanical work. E.g. in a water lifting pump, to lift water from a well. • Today wind energy is used to generate electricity. • A windmill essentially consists of a structure similar to a large electric fan that is erected at some height on a rigid support. Rotary motion of the windmill is used to rotate turbine thereby producing electricity. The electricity produced by single windmill is quite small & cannot be used for commercial purposes. Therefore number of windmills are erected over a large area , which is known as wind energy farm. The energy output of each windmill in the farm is coupled together to get electricity on a commercial scale. • Denmark is known as the country of winds. 25% of total power generated in Denmark is from windmills. • In terms of total output through windmills, Germany is a leader. India is ranked fifth. It is estimated that India has a potential of producing 45000MW through windmills. The largest wind energy farm has been established near Kanyakumari in Tamil Nadu & it generates 380MW of electricity. Advantage of Wind Energy: 1 Wind energy is an environmental friendly & efficient source of renewable energy. 2 It requires no recurring expenses for the production of electricity. Limitation in harnessing wind energy: 1 Wind energy farms can be established only at those places where wind blows for the greater part of the year. 2 Wind speed should also be higher than 15km/h to maintain the required speed of the turbine. 3 There should be some back-up facilities (like storage cells) to take care of the energy needs during a period when there is no wind. 4 Establishment of wind energy farms requires large area of land. For a 1MW generator, the farm needs about 2 hectares of land. 5 The initial cost of establishment of the farm is quite high. 6 Since the tower & blades are exposed to the variation in nature like rain, sun, storm & cyclone, therefore they need a high level of maintenance.
BIO-MASS:
Wood & cow dung has been used as fuel from long time. Since these fuels are plant & animal products, the source of these fuels is said to be bio-mass. However these fuel produce lot of smoke & less heat on burning. Therefore, technological improvements were done to improve the efficiency of these fuels. When wood is burnt in a limited supply of oxygen, water & volatile materials present in it get removed & charcoal is left behind as the residue. Charcoal burns without flames, comparatively smokeless & comparatively produces more heat.
Similarly, cow-dung, plant materials like the residue after harvesting the crops, vegetable waste & sewage are decomposed in absence of oxygen to give bio-gas. Since the starting material is mainly cow-dung, therefore it is popularly known as ‘gobar-gas’
Working of bio-gas plant:
The plant has a dome-like structure built with bricks. A slurry of cow dung& water is made in the mixing tank from where it is fed into the digester. The digester is a sealed chamber in which there is no oxygen. Anaerobic micro-organisms that is no require oxygen decompose or break down complex compounds of cow-dung slurry. It takes a few days for the decomposition process to be complete & generate gases like methane, carbon dioxide, hydrogen & hydrogen sulphide. The bio-gas is stored in the gas tank above the digester from which they are drawn through pipes to use.
Advantages of Bio-Mass Plant:
1 Bio-gas is an excellent fuel as it contains up to 75% methane.
2 Bio-gas burns without smoke.
3 Bio-gas leaves no residue like ash in wood, charcoal and coal burning.
4 Its heating capacity is high.
5 Bio-gas is also used for lighting.
6 The slurry left behind in Bio-gas plant is rich in nitrogen & phosphorous, therefore it is a excellent manure.
7 The large scale utilization of bio-waste & sewage material provides a safe & efficient method of waste-disposal.
8 Bio-gas is renewable source of energy.
Q What is good source of energy?
A A good source of energy is one which: (i) does a large amount of work per unit volume or mass. (ii) is easily available. iii) is easy to store & transport. iv) Is economical.
Q What is a good fuel?
A A good fuel is one which: (i) has high calorific value, i.e. produces large amount of energy on burning in air/oxygen. (ii) produces less smoke on burning. iii) has low cost & is easily available. iv) Has an ignition temperature that is well above the normal temperature.
ENERGY FROM THE SEA:
TIDAL ENERGY: Due to the gravitational pull of mainly the moon on the spinning earth, the water level in the sea rises or falls. Periodic rise & fall of ocean water level occurring twice on each lunar day are called ocean tides – high tide or low-tide. The difference in the levels of ocean water between high-tide and low-tide results in the Ocean Tidal Energy. A tidal dam or a barrier is constructed & the ocean water during the high tide is trapped by the barrier. This water is then allowed to fall down on water turbine thereby converting kinetic energy of flowing water into mechanical energy & then to electrical energy.
It has limitation that only few sites are available for construction of dams & the power generated is intermittent & not very large. Moreover the presently available technologies are very expensive.
WAVE ENERGY: The waves are generated by strong winds blowing across the sea. The kinetic energy possessed by huge waves near the sea-shore can be trapped to rotate turbine thereby generating electricity.
It is a viable proposition only if the waves are very strong. Moreover the presently available technologies are very expensive.
OCEAN THERMAL ENERGY: As the sun rays directly fall on the upper layer of oceans, there is always a temperature difference between the levels of oceans. At some places, there can be difference in temperature upto 20 deg C or more between water at the surface & water at depths upto 2Km. This difference in temperature is exploited to obtain energy in ocean-thermal-energy conversion plants. The warm surface water is used to boil a volatile liquid like ammonia. The vapours of the liquid are then used to run the turbine of generator. The cold water from the depth of the ocean is pumped up & condenses vapour again to liquid.
Its limitation is the conversion efficiency is very low. Moreover the presently available technologies are very expensive.

GEOTHERMAL ENERGY:
Due to geological changes, molten rocks formed in the deeper hot regions of the earth’s crust are pushed upward & trapped in certain regions called ‘hot spots.’ When underground water comes in contact with the hot spot, steam is generated. Sometimes hot water from that region finds outlets at the surface. Such outlets are known as hot springs. The steam trapped in rocks is routed through a pipe to a turbine & used to generate electricity. Cost of producing electricity by geothermal energy is not much. Some of geothermal energy projects are functioning in New Zeaaland, USA.
Its limitation is that there are very few commercially viable sites where such energy can be exploited.

SOLAR ENERGY: • At present rate, sun will continue radiating solar energy for about 5 billion more years. • Only a small part of solar energy reaches the outer layer of the earth’s atmosphere. Nearly half of the sun energy released from sun is absorbed by the atmosphere. • The solar energy reaching unit area at outer edge of the earth’s atmosphere exposed perpendicularity to the rays of the Sun at the average distance between the Sun & the earth is known as the solar constant. It’s value is approx. 1.4kJ per second per square metre or 1.4kW/m2
Solar Cooker: A Solar Cooker is a device which is used to cook food using solar energy. It consists of an insulated metal box or wooden box, which is painted all black from inside. There is a thick glass cover over the box which stops the heat from going out of box (green house effect). Some solar cookers have plane mirror as reflector which focuses the sunrays upon the food to be cooked.
Advantages of Solar cooker: 1. It saves fuel. 2. It does not create pollution 3. The nutrients of food do not get destroyed.
Limitations of solar cooker: 1. It cannot be used during night time. 2. It can not used on cloudy day. 3. It takes longer time to cook. 4. The direction of reflector is to be adjusted frequently. 5. It cannot be used for making chapaties. 6. It can not be used for frying.

Solar Cell: It is a device which converts solar energy i.e. light energy directly into electricity. Solar cells are made of special grade of silicon. The availability of this grade of silicon is very less. A solar cell can develop a voltage of 0.5-1V & can produce about 0.7W of electricity. A large number of solar cells are combined in an arrangement called solar cell panel that can deliver enough electricity for practical use. Silver used for interconnection of the cells in the panel adds to the cost. The solar panels are mounted on specially designed inclined roof tops so that more solar energy is incident over it. Advantages of solar cell: 1. Solar cell has no moving part. 2. Solar cell require less maintenance. 3. Solar cell works quite satisfactory even without focusing device. 4. Solar cell can be set up in remote areas, very sparsely inhabited areas in which laying of a power transmission line may be expensive & not commercially viable. Uses of Solar Cells: Inspite of high cost & low efficiency, solar cells are used for many application: 1. All artificial satellites & space probes (like Mars orbiters) use solar cells as the main source of energy. 2. Radio or wireless transmission systems or TV relay stations in remote locations use solar cell panels. 3. Traffic signals, calculators & many toys are fitted with solar cell.
NUCLEAR ENERGY:
In the nuclear fission process , the nucleus of a heavy atom (such as uranium, plutnium or thorium), when bombarded with low-energy neutrons, split apart into lighter nuclei. When this is done, a tremendous amount of energy is released if the sum of the masses of the products nuclei is less than the mass of the original nucleus.
Energy produced during fission of an atom of uranium is 10 million times more than the energy produced by the combustion of an atom of carbon from coal.
In the nuclear reactor designed for electric power generation, such nucleus ‘fuel’ can be part of a self sustaining fission chain reaction that releases energy at a controlled rate. The released energy can be used to produce steam & further generate electricity.
In all Nuclear reactors / nuclear power station, nuclear fission is used. • In a nuclear fission, the difference in mass, ∆m, between the original nucleus & the product nuclei gets converted to energy E at a rate governed by the famous equation: E=∆mc2 , first derived by Einstein in 1905, where ‘c’ is the speed of light in vacuum. • Nuclear energy is measured in terms of electron volt (eV) where 1eV=1.6X10-19J • Bigger unit is mega electron volt (MeV). 1MeV=106eV

Major hurdles in using Nuclear Power Generation: 1. The storage & disposal of spent or used fuels- the uranium still decaying into harmful subatomic particles (radiations). Improper storage & disposal of nuclear waste results in environmental contamination. 2. There is risk of accidental leakage of nuclear radiation. 3. Cost of installation of nuclear power plant is high 4. There is limited availability of uranium.

• Nuclear energy was first used for destructive purposes before used for power station. • In both nuclear reactor & nuclear bomb, fission chain reaction takes place. • Nuclear power station in India are at: Tarapur (Maharashtra), Rana Pratap Sagar (Rajasthan), Kalpakkam (Tamil Nadu), Narora (UP), Kakrapar (Gujarat), Kaiga (Karnatka). Only 3% of the total electricity generated is from Nuclear energy. In developed countries/ industrialized countries 30% of the total electricity generated is from Nuclear energy. • Nuclear fusion: (Nuclear nuclear fusion is much more safer than fission reaction but fusion requires million of degrees of temperature & million of pascals of pressure) Fusion means joining lighter nuclei to make a heavier nucleus, e.g. hydrogen or hydrogen isotopes join together to make helium: 2H + 2H 3He (+n) Large amount of energy is released. According to Einstein equation also, if the mass of the products is little less than the sum of the masses of the original individual nuclei, large amount of energy is released. Such nuclear fusion reactions are the source of energy in the Sun & other stars. It requires million of degrees of temperature & million of pascals of pressure to take place. • Energy released in nuclear fusion is more than that released in nuclear fission & it does not create pollution problems. • Hydrogen bomb is based on thermonuclear fusion reaction. A nuclear bomb based on the fission of uranium or plutonium is placed at the core of the hydrogen bomb. The nuclear bomb is embedded in a substance which contains deuterium & lithium. When the nuclear bomb (based on fission) is detonated, high temperature generates sufficient energy for the light nuclei to fuse and devastating amount of energy is released.
ENVIRONMENTAL CONSEQUENCES OF EXPLOITING SOURCES OF ENERGY:
Environment is disturbed whenever a source of energy is used to derive energy from it. The source we would choose depends on factors such as ease of extracting energy from that source, the economics of extracting energy from the source, the efficiency of the technology available & the environmental damage that will be caused by using that source. i) Burning of fossil fuels causes air-pollution. ii) Construction of dams destroys large ecosystems & creates problem of rehabilitation of displaced population. iii) Continuous whirling & whistling of windmills cause noise –population & plays havoc with lives of migratory birds. iv) Wave energy effect marine life & seabird population. v) Using wood as fuel results in deforestation which affects environment. vi) Solar cell may be pollution free but the assembly of the device would have caused some environmental damage.
HOW LONG WILL AN ENERGY SOURCE LAST US? i) Fossil fuels (coal, petroleum & natural gas) will get depleted some day as these are exhaustible source of energy. It has been estimated that coal will last for another 200 years whereas known sources of petroleum for another 60 years & those of natural gas for about 40 years. ii) We can get a continuous supply of biomass only if we plant trees in a planned manner. In case, it is not done so, we would fall short of biomass. iii) Geothermal energy is an inexhaustible source of energy. iv) Nuclear energy is also inexhaustible as only small mass of uranium produces large amount of energy, e.g. one atom of uranium produces 10 million times the energy produced by the combustion of an atom of carbon from coal. v) Solar energy, water energy, wind energy & ocean energy are inexhaustible sources of energy.