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Q. What are fossil fuels ? (R.GP.V., Dec. 2015)
Or
Write short note on - Fossil fuel resources. (R.GP.V., June 2012)Or
Write short note on - Fossil fuels. [R.GP.V., May 2019 (IV-Sem.)]
Ans. For introduction of fossil fuels, refer Q.10, section (i). Fossil fuels can be classified into following three types -
(i) Coal Coal is mainly composed of carbon, it also contains hydrogen, oxygen and varying amounts of nitrogen, sulphur and other elements in small quantities. It is developed from decomposition of vegetable matters, trees, plants which fall and buried under the layers of silt. Below the surface of earth they get converted into the coal under heavy pressure, heat and movement of earth crust.
Coal has been the primary energy source since the advent of industrialization. It is available in abundant quantity and will suffice for the next 200 years. Coal on combustion produces various poisonous gases, that is why world is now switching over to other technologies for energy production.
(ii) Oil - Sedimentary rocks containing plants, animals, which are about 10 to 20 crore years old are the sources of mineral oil. Mineral oil is very unevenly distributed over the earth. Almost 40% of the energy needs of the world are fulfilled by oil.
With present stock of 250000 million tonnes of oil, it would be suffice only for 100 years, so an alternative have to be find out.
(iii) Natural Gas - Natural gas is a mixture of lighter hydrocarbons, mainly methane (CH4) and small amount of nitrogen and other impurities such as hydrogen sulphide.
Earlier it was less used, due to its high transportation cost and low thermal efficiency. But now, its utilization rate has been raised upto 90%. It is mainly used for cooking in houses, and as a raw material in petrochemical industry.
Q. What do you understand by fossil fuels? Also explain alternatives (R.GP.V., Nov. 2019)
Ans. For introduction of fossil fuels, refer Q.10, section (i). Fossil fuels can be classified into following three types -
(i) Coal Coal is mainly composed of carbon, it also contains hydrogen, oxygen and varying amounts of nitrogen, sulphur and other elements in small quantities. It is developed from decomposition of vegetable matters, trees, plants which fall and buried under the layers of silt. Below the surface of earth they get converted into the coal under heavy pressure, heat and movement of earth crust.
Coal has been the primary energy source since the advent of industrialization. It is available in abundant quantity and will suffice for the next 200 years. Coal on combustion produces various poisonous gases, that is why world is now switching over to other technologies for energy production.
(ii) Oil - Sedimentary rocks containing plants, animals, which are about 10 to 20 crore years old are the sources of mineral oil. Mineral oil is very unevenly distributed over the earth. Almost 40% of the energy needs of the world are fulfilled by oil.
With present stock of 250000 million tonnes of oil, it would be suffice only for 100 years, so an alternative have to be find out.
(iii) Natural Gas - Natural gas is a mixture of lighter hydrocarbons, mainly methane (CH4) and small amount of nitrogen and other impurities such as hydrogen sulphide.
Earlier it was less used, due to its high transportation cost and low thermal efficiency. But now, its utilization rate has been raised upto 90%. It is mainly used for cooking in houses, and as a raw material in petrochemical industry.
Non-Conventional (or Renewable) Energy Sources - Some commonly used renewable energy sources are -
(i) Sun (ii) Wind (iii) Sea (iv) Geothermal
(v) Biothermal.
These sources are almost inexhaustible and get replenished by natural process. Further, their use doesn't cause environmental pollution. However, their energy cannot be used on commercial basis. These sources are discussed in brief below-
Sun's energy can be utilised as thermal and photovoltaics. Sun can provide 178 billion MW, which is 20,000 times the world's demand, however it could not be utilised completely. Wind energy uses the high wind velocity available in certain parts. It can be used for pumping the water or power generation. Coastal, hilly and valley areas are suitable for this purpose. Geothermal energy utilises the heat available in the centre of the earth. It can be used for cooling by using heat in vapour absorption system.
Energy from seas can be used as wave, tidal or ocean thermal energy. About 13 kW per metre height of the wave can be generated. Ocean thermal energy conversion utilises the temperature difference between worm surface sea water (at 28°C) and the cold deep sea water at 5-7°C at a depth of 800-1000 m in tropical areas. The total potential of sea is estimated as 50000 MW from ocean thermal energy conversion, 40000 MW from wave energy and 10000 MW from tidal.
Biomass in the form of wood, agricultural waste, etc. is also a potential source of energy. These can be burnt directly to generate steam for use in steam turbine or they can be gasified to use as gas in I.C. engines for agricultural pumping or power generation.
(i) Coal Coal is mainly composed of carbon, it also contains hydrogen, oxygen and varying amounts of nitrogen, sulphur and other elements in small quantities. It is developed from decomposition of vegetable matters, trees, plants which fall and buried under the layers of silt. Below the surface of earth they get converted into the coal under heavy pressure, heat and movement of earth crust.
Coal has been the primary energy source since the advent of industrialization. It is available in abundant quantity and will suffice for the next 200 years. Coal on combustion produces various poisonous gases, that is why world is now switching over to other technologies for energy production.
(ii) Oil - Sedimentary rocks containing plants, animals, which are about 10 to 20 crore years old are the sources of mineral oil. Mineral oil is very unevenly distributed over the earth. Almost 40% of the energy needs of the world are fulfilled by oil.
With present stock of 250000 million tonnes of oil, it would be suffice only for 100 years, so an alternative have to be find out.
(iii) Natural Gas - Natural gas is a mixture of lighter hydrocarbons, mainly methane (CH4) and small amount of nitrogen and other impurities such as hydrogen sulphide.
Earlier it was less used, due to its high transportation cost and low thermal efficiency. But now, its utilization rate has been raised upto 90%. It is mainly used for cooking in houses, and as a raw material in petrochemical industry.
Non-Conventional (or Renewable) Energy Sources - Some commonly used renewable energy sources are -
(i) Sun (ii) Wind (iii) Sea (iv) Geothermal
(v) Biothermal.
These sources are almost inexhaustible and get replenished by natural process. Further, their use doesn't cause environmental pollution. However, their energy cannot be used on commercial basis. These sources are discussed in brief below-
Sun's energy can be utilised as thermal and photovoltaics. Sun can provide 178 billion MW, which is 20,000 times the world's demand, however it could not be utilised completely. Wind energy uses the high wind velocity available in certain parts. It can be used for pumping the water or power generation. Coastal, hilly and valley areas are suitable for this purpose. Geothermal energy utilises the heat available in the centre of the earth. It can be used for cooling by using heat in vapour absorption system.
Energy from seas can be used as wave, tidal or ocean thermal energy. About 13 kW per metre height of the wave can be generated. Ocean thermal energy conversion utilises the temperature difference between worm surface sea water (at 28°C) and the cold deep sea water at 5-7°C at a depth of 800-1000 m in tropical areas. The total potential of sea is estimated as 50000 MW from ocean thermal energy conversion, 40000 MW from wave energy and 10000 MW from tidal.
Biomass in the form of wood, agricultural waste, etc. is also a potential source of energy. These can be burnt directly to generate steam for use in steam turbine or they can be gasified to use as gas in I.C. engines for agricultural pumping or power generation.
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