What is energy? Write various renewable and non-renewable sources of energy. Discuss role of fossil fuels in energy scenario of India along with their environmental threats. | Define renewable and non-renewable sources of energy with examples

Energy & Environmental Engineering | Environmental Science | HOTS Questions | Important Questions

Q. What is energy? Write various renewable and non-renewable sources of energy. Discuss role of fossil fuels in energy scenario of India along with their environmental threats.

Ans. Energy is the capacity of doing work. It is most important and primary input for development. All living organisms needs energy for their operations, which they derived from the environment. Man has required and used the energy ever since he came on the earth. Primitive man gets energy in the form of food by eating plants and animals. Later on he discovered fire and with the advancement he discovered various energy sources, which he used for his domestic, industrial, transportation, agricultural and other needs.

Energy is available in number of forms such as mechanical, thermal, electrical, chemical, biological energy and energy in matter. Energy is also a 5) fundamental quantity, which is measured in Joules (J) and can be defined as the work done, when a force of one Newton moves through one metre.

Renewable Energy Sources - Renewable energy sources are those which are virtually inexhaustible and can be replenished after their use. They are biomass based sources and are available in unlimited amount in nature. These include solar, wind, water, geothermal, ocean and biomass energy. Nuclear energy, can also be considered as a renewable source, if atomic minerals are used in a fast breeder reactor.

Non-renewable Energy Sources Non-renewable energy sources are

those natural resources which are exhaustible and cannot be replenished once used. These are developed over a long period due to physical, chemical and biological actions below the earth surface. They are available in limited amount. They include fossil fuels such as coal, oil and natural gas.

(i) Coal - It has been estimated that, about 6000 billion tonnes of coal lies under the earth out of which 200 billion tonnes has been used. In India, coal contributes about 60% of our total energy requirements. India is the third largest coal producing country in the world. Our total coal reserves are estimated to be about 68 billion tonnes, and with our current rate of mining, 323 million tonnes per year, they will be suffice for about 200 years. But out of 68 billion tonnes only 21 billion tonnes are in the form of proved reserves and about 80% of our proved reserves is with an ash content of more than 20% further 50% of our coal deposites are located in Bihar and Bengal, and need to be transported over a long distance for use.

Coal has very low calorific value, and produces various air pollutants such as CO2, CO, H2S and SO2 on combustion. These gases are responsible for global warming, acid rain and many other hazardous effects. Thermal power plants using coal produce a large quantity of ash. A 200 MW plant using 30000 tonnes of coal per month will release about 4000 tonnes of ash. This ash need to be disposed off in a safe manner.

(ii) Oil-U.S.A., Mexico, U.S.S.R. and the West Asian region (Iraq, Saudi Arabia, Kuwait, Iran, United Arab Emirates, Qatar and Bahrain) are the major oil producing countries of the world.

In India potential oil bearing areas are Assam, Tripura, Manipur, West Bengal, Ganga valley, Punjab, Himachal Pradesh, Kutch, Eastern and Western coastal area (in Tamil Nadu, Andhra Pradesh and Kerala ). Andaman and Nikobar Islands, Lakshadweep are also having oil bearing areas. Bombay high (115 km from the shore) is the richest oil field of the country. The latest oil deposits have been found in off shore areas of the coasts of Godavari, Krishna, Kaveri and Mahanadi.

Although with oil, there is no problem of ash handling, still its combustion produces highly poisonous gases like H2S, CO, and SO2. Further, transportation of oil is very risky and any leakage can cause serious damage. Leakage of oil during transportion through sea can produce disastrous effects.

(iii) Natural Gas-The production of natural gas in India has raised from 2358 million cubic metres in 1980-81 to 19380 million cubic metres now-a-days. At this rate our reserves of natural gas (about 700 billion cubic metres) will suffice only for next 20 years.

Natural gas is much less pollutant as compared to other fossil fuels.

 Q. Define renewable and non-renewable energy resources. (R.GP.V., June 2016)

Or
Define renewable and non-renewable sources of energy with examples. (R.GP.V., Dec. 2012)

Ans. Renewable Energy Sources - Renewable energy sources are those which are virtually inexhaustible and can be replenished after their use. They are biomass based sources and are available in unlimited amount in nature. These include solar, wind, water, geothermal, ocean and biomass energy. Nuclear energy, can also be considered as a renewable source, if atomic minerals are used in a fast breeder reactor.

Non-renewable Energy Sources Non-renewable energy sources are

those natural resources which are exhaustible and cannot be replenished once used. These are developed over a long period due to physical, chemical and biological actions below the earth surface. They are available in limited amount. They include fossil fuels such as coal, oil and natural gas.