Good sources of energy are
(I) It should have high calorific value.
(II) It does a huge amount of work per unit mass.
(III) It should be easy to handle.
(IV) It should be easy to store and transport.
(V) It must be cheap.
(VI) It produces less amount of smoke and is eco friendly.
A good fuel should have a high calorific value that is the amount of heat produced on burning, does not produce a lot of smoke, and is easily available.
Natural gas is a good source of energy and can be used for heating and cooking food because it is a clean source of energy burn without smoke. Although it is highly inflammable, it is easy to use, transport, and has high calorific value.
The fossil fuels disadvantages are as follows:
(a) coal and petroleum while burning produces a lot of pollutants that cause air pollution.
(b) They release oxides of carbon, nitrogen, sulphur, etc. that cause acid rain, which affects the soil fertility and potable water.
(c) Burning of fossil fuels produce gases such as carbon dioxide that causes global warming.
Non conventional sources of energy are better than Fossil fuels, which have been traditionally used by human beings as energy sources, are non-renewable sources of energy. These sources of energy are limited and cannot replenish on their own. They are being consumed at a large rate. If this rate of consumption continues, then the fossil fuels would be exhausted from the Earth. Therefore, we have to conserve the energy sources. Hence, we should look for alternate sources of energy.
Nowadays, windmills are used to generate electricity whereas earlier they were used to harness wind energy to do mechanical work such as lifting/drawing water from a well.. Through windmills, the kinetic energy of wind is converted into electricity. The rotatory motion of the blades turns the turbine of the electric generator to generate electricity. waterfalls potential energy is converted to electricity with the help of turbines. Since waterfalls are few in number, water dams have been constructed in large numbers. Nowadays, hydro-dams are used in order to harness potential energy of stored water. In water dams, water falls from a height on the turbine, which produces electricity.
A concave mirror is a converging mirror therefore it would be best suited in a solar cooker because it converges the sunlight in a very small area of the solar cooker and a high temperature is produced in it which is sufficient to cook the food.
The various forms of energy can be obtained from the ocean these are:
a. ocean thermal energy
b. wave energy and
c. tidal energy
Limitations of Tidal Energy:
i. Limited areas around the world which are suitable for building tidal dams.
ii. During high and low tides the rise and fall of sea-water is not enough to generate electricity on a large scale.
Limitations of Wave Energy:
In the world there are limits where the waves strike the shore lines with sufficient power that is sufficient to generate electric energy from the kinetic energy of the waves.
Limitations of Ocean Thermal Energy:
Ocean thermal plant involves high cost. To convert ocean thermal energy into electricity, a great variation in temperature difference of 20°C (or more) between the surface water of the ocean and deeper water is needed for operating OTEC power plants.
i. Limited areas around the world which are suitable for building tidal dams.
ii. During high and low tides the rise and fall of sea-water is not enough to generate electricity on a large scale.
The heat energy of the Earth is used to generate electricity by geothermal plants . This heat energy of the Earth is known as geothermal energy.When there are geological changes, the molten rocks present in the core of the earth are pushed to the earth’s crust. This forms regions of hot spots. Steam is generated when the underground water comes in contact with these hot spots forming hot springs. This trapped steam is used to generate electricity in the geothermal power plants.
The nuclear energy advantages are as follows:
a) Fusion of four hydrogen atoms produces a huge amount of energy approximately equal to 27 MeV.
b) Large amount of energy is produced per unit mass.
c) It does not produce smoke. It is clean energy.
d) Fission of one atom of uranium produces 10 million times the energy released by burning of one atom of carbon.
Yes , no source of energy can be pollution-free. They might cause adverse effects on the environment to some extent. It is considered that solar cells are pollution-free. However, even their making causes environmental damage indirectly.
Also, in the case of nuclear energy, there is no waste produced after the fusion reactions. However, it is not totally pollution-free. To start the fusion reactions, approximately 107 K temperature is required, which is provided by fission reactions. The wastes released from fission reactions are very hazardous. Hence, no source of energy is pollution-free.
Hydrogen Gas is cleaner to CNG. hydrogen is waste-free. The fusion of hydrogen does not produce any waste. Whereas CNG contains hydrocarbons. Therefore, it has carbon contents. Carbon is a form of pollutant present in CNG. Hence, hydrogen is cleaner than CNG.
Two renewable sources of energy are as follows:
(a) Wind: Wind energy is derived from air blowing with high speed. Wind energy is harnessed by windmills in order to generate electricity. Air blows because of uneven heating of the Earth. Since the heating of the Earth will continue forever, wind energy will also be available forever.
(b) Sun: The energy derived from the Sun is known as solar energy. Solar energy is produced by the fusion of hydrogen into helium, fusion of helium into other heavy elements, and so on. A large amount of hydrogen and helium is present in the Sun. Therefore, solar energy can replenish on its own. The Sun has 5 billion years more to burn. Hence, solar energy is a renewable source of energy.
Two exhaustible energy sources are as follows: coal and wood
(a) Coal: It is formed from the remains of dead plants and animals that have been buried under the earth’s crust for millions of years. It takes millions of years to produce coal. Industrialization has increased the demand of coal. However, coal cannot replenish within a short period of time. it is a nonrenewable or exhaustible source of energy.
(b) Wood: It is obtained from forests. Deforestation at a faster rate has caused a reduction in the number of forests on our planet. It takes hundreds of years to grow a forest. If deforestation is continued at this rate, then there would be no wood left on the Earth. Hence, wood is an exhaustible source of energy.
(b) during cloudy days solar heater cannot be used because , A solar water heater uses solar energy to heat water. It requires bright and intense sunlight to function properly. On a cloudy day, the sunlight reflects back in the sky from the clouds and is unable to reach the ground. Therefore, solar energy is not available for the solar heater to work properly.
Due to Industrialisation the demand for energy increases . Fossil fuels are easily accessible sources of energy that fulfil this demand. The increased use of fossil fuels has an adverse effect on the environment. Large consumption of fossil fuels increases the greenhouse gas in the atmosphere, resulting in global warming and a rise in the sea level.
It is not possible to reduce the consumption of fossil fuels. However, some preventive measures can be taken such as using electrical appliances wisely and not wasting electricity. Unnecessary usage of water should be avoided. Public transport systems with mass transit must be adopted on a large scale. These small steps may help in reducing the consumption of natural resources and conserving them.
(c) nuclear energy is not a biomass.
Biomass is a source of energy that is obtained from plant materials and animal wastes.Wood is a plant material, gobar gas is formed from animal dung, and coal is a fossil fuel obtained from the buried remains of plants and animals, these are biomass products. Nuclear energy is released during nuclear fission and fusion. In nuclear fission, uranium atom is bombarded with low-energy neutrons. Hence, uranium atom splits into two relatively lighter nuclei. This reaction produces huge amount of energy. In nuclear fusion reaction, lighter nuclei are fused together to form a relatively heavier nuclei. This reaction produces a tremendous amount of energy.
C) Nuclear energy is not derived from sun energy.
Nuclear energy is released during nuclear fission and fusion. In nuclear fission, uranium atoms are bombarded with low-energy neutrons, uranium atoms split into two relatively lighter nuclei. This reaction produces a huge amount of energy. In nuclear fusion reaction, lighter nuclei are fused together to form a relatively heavier nuclei. The energy required to fuse the lighter nuclei is provided by fission reactions. This reaction produces a tremendous amount of energy. These reactions can be carried out in the absence or presence of sunlight. There is no effect of sunlight on these reactions. Hence, nuclear energy is not ultimately derived from the Sun's energy.
Geothermal energy, wind energy, and biomass are all ultimately derived from solar energy.
Coal and petroleum are Fossil fuels and are energy sources,obtained from the Earth’s crust. They are directly available to human beings for use.So , fossil fuels are the direct source of energy. These are non-renewable sources of energy because these cannot be replenished in nature. Fossil fuels take millions of years for their formation. If the present fossil fuel of the Earth gets exhausted, its formation will take several years. Fossil fuels are also very costly.
On the other hand, solar energy is a renewable and direct source of energy. The Sun has been shining for several years and will do so for the next five billion years. Solar energy is available free of cost to all in unlimited amounts. It replenishes in the Sun itself.
Both Biomass and hydro-electricity are renewable sources of energy. Biomass is derived from remaining plants and animal wastes.So , it is naturally replenished. Wood, gobar gas, etc. are some of the examples of biomass.
Hydro-electricity, on the other hand, is obtained from the potential energy stored in water at a height. Energy from it can be produced again and again. It is harnessed from water and obtained from mechanical processes.
(a) limitations of extracting energy from wind is that a windmill requires wind of speed more than 15 km/h to generate electricity. Also, a large number of windmills are required, which covers a huge area.
(b) Strong ocean waves are required in order to extract energy from waves.
(c) Very high tides are required in order to extract energy from tides. Also, occurrence of tides depends on the relative positions of the Sun, moon, and the Earth.
(a)That source of energy that replenishes in nature is known as a renewable source of energy. Sun, wind, moving water, biomass, etc. The source of energy that does not replenish in nature is known as a non-renewable source of energy. Coal, petroleum, natural gas, etc. are some of the examples of non-renewable sources of energy.
(b)those sources of energy, which will deplete and exhaust after a few hundred years are exhaustible . Coal, petroleum, etc. are the exhaustible sources of energy.Inexhaustible resources of energy are those sources, which will not exhaust in future. These are unlimited. Biomass is one of the inexhaustible sources of energy.
Yes. The options given in (a) and (b) are the same.
An ideal source of energy must be:
i) Easy to store and transport
ii) Easily accessible
iii) Environment friendly
iv) high calorific value
v) cheap
Solar cooker uses the Sun's energy to heat and cook food. It is an inexhaustible and clean renewable source of energy. It is free for all and available in unlimited amounts. Hence, operating a solar cooker is not expensive.
Disadvantage of a solar cooker is that it is very expensive. It does not work without sunlight. Hence, on cloudy days, it becomes useless.
The places where the days are too short or places with cloud covers round the year, have limited utility for solar cookers.
Non- conventional resources are the renewable process of energy which is continuously replenished (refill or freshen up again) by the natural resources. Electricity or energy generated by the wind by windmills, biomass, solar energy; all are the examples of non-conventional resources.
Two main reasons for the need to harness non- conventional sources of energy are following:-
1. Exhaustible resources like fossil fuels take millions of years to form and decrease in these resources in future lead to the shortage for the future generation which in turn has serious repercussions on the growth of the natural economy; but non-conventional resources like wind, solar energy can be used continuously. Thus non- conventional resources need to be harnessed for future use.
2. Exhaustible resources pollute the environment when they are being used while non- conventional did not produce any harmful effect on the environment. They are pollution free, renewable, environment friendly so they are the best choice.
There are mainly three different ways of harnessing energy from the ocean:- Tidal energy, Wave energy and Ocean thermal energy.
Two ways are following:-
1. Tidal Energy:- The level of water in the sea rises and falls by the gravitational pull of mainly the moon on spinning earth, and this is called high and the low tides. And the difference in between the high and low tides is known as tidal energy. This energy is obtained by constructing a dam across the narrow opening to sea and a turbine is fixed which converts tidal energy to electricity.
2. Ocean Thermal Energy:- Water at the surface of the sea is heated by sunlight but the deeper water is cold in sea. This energy is obtained from the temperature difference in ocean thermal energy conversion plants. The warm surface of water is used to boil the volatile liquid and then these vapours of liquid like ammonia. These vapours are then used to run the turbine of the generator. And, the cold water from the deeper section of the sea or ocean pumped and condenses vapours again into liquid.
Petroleum, coal and natural gas are the fossil fuels. Burning of fossil fuels release oxides of carbon, nitrogen and sulphur in the atmosphere which also leads to acid rain that are produced by the combustion of fossil fuels, smelters, power plants, industries etc. sulphuric acid (H2SO4) and nitric acid (HNO3) is produced and contributes 60-70% or 30-40% respectively of the acidity and it automatically pollutes the environment and leads to air pollution. To minimize the environmental pollution caused by burning of fossil fuels various measures are taken:-
1. Conventional fuels like firewood, coal and oil should be replaced by electricity or natural gas like CNG which do not emit sulphur oxides.
2. Pollution free fuels like alcohol, hydrogen or battery power should be developed for automobiles. Good quality fuel should be used in motor vehicles which can reduce SO2 pollution.
3. Trees should be grown in all available spaces which use carbon dioxide and release oxygen; this purifies air.
Solar cooker is a device which converts solar energy into heat that is used to heat, cook and pasteurize drinks, food and other materials by using direct sunlight. Solar cookers covered with the glass plate and some solar cookers achieve high temperature by using the plane mirrors. Glass sheets provide warmth in the green house, receives less amount of solar radiation.
Plane mirror reflects the sunlight by increasing the intensity of solar energy and glass sheet prevents the heat escape of the sunlight by absorbing inside the solar cooker.
Solar energy is extremely beneficial for the environment and as well as to the private economy. Some advantages of solar cell are following:-
1. Solar cells (or solar plates) are charged by the sunlight and used to generate electricity. Thus solar cells are a renewable source of energy.
2. It does not produce environmental pollution and is environment friendly.
3. It requires low maintenance, reduces electricity bills.
4. Solar cells can be used for various purposes like electricity or heat (Solar thermals). It can be used in homes and large companies too.
Biomass is organic matter which is made from living organisms like plants and animals. Biomass is used to fuel the electric generators. The energy from the living organisms is obtained from the direct or indirect means. When biomass is burned to create heat is a direct method and conversion into biofuel is an indirect method.
Various are the methods to obtain bio-energy using biomass:-
1. Plants and animals produce or we plant trees and obtain wood (fire- wood) these all are used as a fuel for a very long time.
2. Cow- dung cakes can be used as a heating source or as a fuel.
3. Residue of the plant materials like vegetable waste, sewage or cow- dung cakes are first decomposed in the absence of oxygen to make bio- gas or from cow- dung is known as ‘gobar- gas’.
4. Bio- gas is used in the gas engines to convert this energy into electrical energy and heat.
Limitations in obtaining energy from wind are as follows:-
1. To generate the electricity, high wind velocity is required to rotate the turbine. The wind speed should be higher than 15km/h to maintain the required speed of the turbine.
2. Wave energy only depends on the location; it cannot be obtained from the small area. So, windmills should be placed over the large area which is also known as wind energy farm. Initial cost of setting up the windmill is very high.
3. For the production of electricity, it should be continuous and consistent. But unfortunately, it cannot be because the turning of the turbine only depends on the wind.
The nuclear power is harnessed in the nuclear power plants by the nuclear fission process. Fission process occurs in a Uranium atom which produces a high amount of energy as 10 million times the energy produced from carbon.
Nuclear fission:- Nuclear fission is the phenomenon of splitting a heavy nuclei into two or more light nuclei. In this, the difference in the mass ∆m, between the original nucleus and the product nuclei gets converted to energy E at the rate a, and governed by the Einstein- mass energy relation:-
E = ∆mc2 ; Where c is the velocity of light
Advantages:-
1. Less use of fossil fuels implies lower emission of greenhouse gas.
2. It provides 200 mev energy in the fission of a single U235 nucleus.
3. Further this released energy is used as heat and then this heat is used to boil the water which releases steam. Then the steam is used to turn the turbine to generate electricity.
Solar energy can be harnessed directly by using solar cookers, solar heaters or solar cells.
In a solar cooker, the heat energy by the sun is used for cooking purposes. Solar cooker is a device which converts solar energy into heat that is used to heat, cook and pasteurize drinks, food and other materials by using direct sunlight. Solar cookers covered with the glass plate and some solar cookers achieve high temperature by using the plane mirrors. Glass sheets provide warmth in the green house, receives less amount of solar radiation.
In a solar heater, the heat energy is used to heat the water.
Solar cells are used to convert heat energy into the electricity. Solar cell device is small in size, bluish- black in colour. These are made of p & n type semiconductor. These small solar cells are combined together to form a solar module, then these solar modules themselves combined to form a bigger unit called solar panels. Photovoltaic cells are attached to the panels to convert sunlight into electricity. As we know, light consists of photons when these fast moving photons stick the solar panel; they are captured and convert them into the flow of electrons which generate electric current. A single cell can generate a few volts of electricity. So, a solar panel job is to combine the energy produced by many cells to make a useful amount of electric current and voltage.
Limitations:
1. Solar energy cannot be used or available at night or when the sun is hidden in the clouds which happen mostly in the winter or the rainy days.
2. The domestic use of solar cells is not possible due to high cost.
And, these limitations can be overcome by the following ways:-
Conventional sources are the non- renewable process of energy which can’t be used continuously or replenished by natural resources. Examples:- Coal, petroleum, firewood etc. these are the fossil fuels.
And, non- conventional sources are the renewable process of energy which is continuously replenished (refilled or freshen up again) by the natural resources. Examples:- solar energy, biomass or biogas, tidal energy, wave energy, ocean thermal energy, nuclear energy etc.
Methods to harness the non- conventional sources of energy are following:-
1. Tidal Energy: The level of water in the sea rises and falls by the gravitational pull of mainly the moon on spinning earth, and this is called high and the low tides. And the difference in between the high and low tides is known as tidal energy.
This energy is harnessed by constructing a dam across the narrow opening to sea and a turbine is fixed which converts tidal energy to electricity.
2. Wave Energy: Kinetic energy possessed by large waves near the sea and used to generate electricity. And, these waves are generated by the strong winds. Wave energy can be trapped only where waves are very strong. Various devices have been used to trap wave energy for turning the turbine and production of electricity.
3. Ocean Thermal Energy: Water at the surface of the sea is heated by sunlight but the deeper water is cold in sea. This energy is obtained from the temperature difference in ocean thermal energy conversion plants. The warm surface of water is used to boil the volatile liquid and then these vapours of liquid like ammonia. These vapours are then used to run the turbine of the generator. And, the cold water from the deeper section of the sea or ocean pumped and condenses vapours again into liquid.
4. Nuclear Energy: It is harnessed by the fission process in nuclear power plants to convert the energy into the electricity with the help of nuclear reactors.
5. Solar Energy: solar energy is harnessed by using solar cells, solar cookers, solar panels etc. which is charged by the direct sunlight.
Non-conventional resources are the renewable process of energy which is continuously replenished (refill or freshen up again) by the natural resources. Electricity or energy generated by the wind by windmills, biomass, solar energy; all are the examples of non- conventional resources. Two main reasons for the need to harness non- conventional sources of energy are following:-
1. Exhaustible resources like fossil fuels take millions of years to form and decrease in these resources in future lead to the shortage for the future generation which in turn has serious repercussions on the growth of the natural economy; but non-conventional resources like wind, solar energy can be used continuously. Thus non-conventional resources need to be harnessed for future use.
2. Exhaustible resources pollute the environment when they are being used while non-conventional did not produce any harmful effect on the environment. They are pollution free, renewable, environment friendly so they are the best choice.
There are mainly three different ways of harnessing energy from ocean:- Tidal energy, wave energy and Ocean thermal energy and these are following:-
1. Tidal Energy:- The level of water in the sea rises and falls by the gravitational pull of mainly the moon on spinning earth, and this is called high and the low tides. And the difference in between the high and low tides is known as tidal energy. This energy is harnessed by constructing a dam across the narrow opening to sea and a turbine is fixed which converts tidal energy to electricity.
2. Wave Energy:- Kinetic energy possessed by large waves near the sea and used to generate electricity. And, these waves are generated by the strong winds. Wave energy can be trapped only where waves are very strong. Various devices have been used to trap wave energy for turning the turbine and production of electricity.
3. Ocean Thermal Energy:- Water at the surface of the sea is heated by sunlight but the deeper water is cold in sea. This energy is obtained from the temperature difference in ocean thermal energy conversion plants. The warm surface of water is used to boil the volatile liquid and then these vapours of liquid like ammonia. These vapours are then used to run the turbine of a generator. And, the cold water from the deeper section of the sea or ocean pumped and condenses vapours again into liquid.
Consequences of using fossil fuels:
Petroleum, coal and natural gas are the fossil fuels. Burning of fossil fuels release oxides of carbon, nitrogen and sulphur in the atmosphere which also leads to acid rain that are produced by the combustion of fossil fuels, smelters, power plants, industries etc. sulphuric acid and nitric acid is produced and contributes 60-70% or 30-40% respectively of the acidity and it automatically pollutes the environment and leads to air pollution. And, air pollution leads to health hazards to the human and the animal’s health. By increasing the amount of gases specially carbon dioxide will lead to global warming. Non- conventional resources are the renewable process of energy which is continuously replenished by the natural resources.
Electricity or energy generated by the wind by windmills, biomass, solar energy; all are the examples of non- conventional resources. The steps to minimize the environmental pollution caused by various measures sources of energy including non-conventional sources of energy are following:-
1. Conventional fuels like firewood, coal and oil should be replaced by electricity or natural gas like CNG which do not emit sulphur oxides. Thus use public transport.
2. Pollution free fuels like alcohol, hydrogen or battery power should be developed for automobiles. Good quality fuel should be used in motor vehicles which can reduce SO2 pollution.
3. Trees should be grown (Afforestation) in all available spaces which use carbon dioxide and release oxygen; this purifies air.
4. Avoid misuse of the energy or electricity to reduce the consumption level.
5. Use catalytic converters that can convert oxides of nitrogen to nitrogen that will control the automobile exhaust.
6. Kyoto protocol is linked to the United Nations Framework Convention on Climate Change (UNFCCC) which enables developed countries to acquire greenhouse gases reduction or to automatically reduce environmental pollution.
Yes, I agreed to the statement that energy from various sources have been considered to have been derived from the sum, the reasons are as follows:-
In the wave energy, strong winds are generated due to the sun and the wave energy is generated by the waves that are generated by the strong winds blowing across the sea. In the Ocean thermal energy, Water at the surface of the sea is heated by sunlight but the deeper water is cold in the sea. This energy is obtained from the temperature difference which is due to the sunlight. Warm surface of the water is used to boil the volatile liquid and then these vapours of liquid like ammonia. These vapours are then used to run the turbine of the generator. In solar energy, the phenomenon of photoelectric effect (electricity production by the light) is possible only in the presence of the sun.
Energy from the fossil fuels are obtained by a lot of pressure and heat because they are buried deep inside the earth’s crust which are made by the dead organic matter. Energy can also be obtained from the water of seas, rivers etc. the water gets evaporated and falls at different places as snow or rainfall. And then this water gets collected in the large dams which allow it to flow after getting filled and then this water is used to rotate the turbines to generate electricity.
Biomass is organic matter which is made from the living organisms like plants and animals which is used to fuel the electric generators. The energy from the living organisms is obtained from the direct or indirect means. When biomass is burned to create heat is a direct method and conversion into biofuel is an indirect method. Cow-dung cakes (used as heating source), plants and animal products or we planted trees and obtained wood (fire- wood) these all are used as a fuel for a very long time.
Residue of the plant materials like vegetable waste, sewage or cow- dung cakes are first decomposed in the absence of oxygen to make bio- gas or from cow- dung is known as ‘gobar- gas’.
Working of the biogas plant:
Biogas plants are dome-like structures made with bricks. A semi- liquid mixture (slurry) of cow- dung and water is made in the mixing tank from where it is fed into the digester. Digester is a sealed chamber where no oxygen can enter. The complex compounds of cow- dung slurry break down with the help of anaerobic microorganisms. It takes a few days to complete the decomposition process and to generate the gases- methane, carbon dioxide, hydrogen and hydrogen sulphide. Then the biogas is stored in the gas tank above the digester from which they are drawn through the pipes.
Biogas is an excellent fuel which contains 75% of methane. It burns without smoke and does not leave any residual ash; heating capacity is very high. The slurry that is left behind can be used as excellent manure which is rich in nitrogen and phosphorus.
Maximum utilisation of bio- waste and sewage material provides a safe method for the waste- disposal.
Diagram: