Cce Bane or Boon

Characteristics of good fuel/source of energy i) It should have a high energy output per unit mass or volume. ii) It should be easily available. iii) It should be easy to store and transport. iv) It should be economical.
v) It should be easy to handle and use vi) It should be eco-friendly

Classification of sources of energy In daily life, we use number of sources of energy like coking gas, cow dung cakes, wood, kerosene etc. for cooking and other domestic works whereas diesel, petrol, CNG are being used for transportation, electricity is being used for many other uses like running fan, refrigerators etc .Sources of energy can be divided into two major groups as 1) Conventional source and non-conventional source of energy 2) Renewable source and non- renewable source of energy
Conventional sources of energy-:
These sources of energy are being used by mankind for last many-many years and most of our energy needs are met by these sources. Example of these sources are-: i. Fossil fuels like natural gas, petrol, diesel, coal etc. ii. Energy from flowing water (hydroelectricity). iii. Energy from wind. iv. Bio-mass energy.
Non-conventional source of energy-: Those sources of energy which are recently explored to meet our ever increasing demand of energy are termed as non-convential source of energy or alternative source of energy. Examples of non-conventional sources of energies are-: i. Solar energy ii. Energies from oceans i.e. Tidal energy, wave energy, ocean thermal energy iii. Geothermal energy iv. Nuclear energy
Renewable and non- renewable source of energy
.Renewable source of energy-:
Those sources of energy which are continuously produced in nature and are practically inexhaustible. These are called renewable or non-depletable sources of energy. Examples of renewable sources of energies are -: 1. Solar energy 2. wind energy 3. Energy from flowing water (hydroelectricity). 4. Energies from oceans i.e. Tidal energy, wave energy, ocean thermal energy 5. Geothermal energy 6. Bio-mass energy. 7. Wood
Non- renewable source of energy-: Those sources of energy which are likely to be exhausted in coming future. These are also called depletable sources of energy. Examples of non-renewable sources of energy are-: 1. Coal 2. Petroleum 3. Natural gas

Conventional sources of energy
Fossil fuels They are fuels formed inside the earth from the remains of plants and animals after millions of years. The fossil fuels are coal, petroleum and natural gas. Fossil fuels are non-renewable sources of energy so they should be conserved and used judiciously. Disadvantages of fossil fuels:- a. Burning of fossil fuels release gases and harmful particles which causes air pollution. b. Burning of fossil fuels release acidic oxides of sulphur and nitrogen which causes acid rain which is harmful for living organisms, affects soil and water, causes damage to buildings, corrosion of metals etc. c. Burning of fossil fuels release a large amount of carbon dioxide gas which increases the temperature atmosphere and causes global warming (greenhouse effect) d. It is non-renewable source of energy and takes millions of years for transformation

Thermal power plant
In thermal power plants the heat energy produced by burning fossil fuels like coal, petroleum or natural gas is used to heat water and change it into steam which rotates the turbines of generators to produce electricity.
Hydro power plants
In hydro power plants water from rivers are stored by constructing dams on height. The water from the dam flows down through pipes and rotates the turbines of generators to produce electricity. Traditional use Earlier the kinetic energy of flowing water or the potential energy of water at height in form of waterfalls were used as source of energy which was converted to electricity with help of turbines. Since waterfalls are few in number, water dams have been created in large numbers. Hydro dams are used to harness potential energy of water and convert it into electric energy Advantages:- i) Flowing water is a renewable source of energy. ii) The electricity produced does not cause pollution. iii) The water stored in dams can also be used to control floods and for irrigation. Disadvantages:- a. The initial cost is high. b. Large areas of land get submerged and the decomposition of vegetation produces methane gas which is a greenhouse gas. c. It causes displacement of people from large areas of land. d. Construction of dams adversely affect ecosystem e. It can be constructed only at a limited number of places where river flows throughout the year.
Bio-Mass
The waste materials and dead parts of living things are called biomass. E.g.:- wood, animal dung, vegetable waste, agricultural waste, sewage etc. But it has some limitations that it does not produce much heat on burning and a lot of smoke is given out when they are burnt. The only advantage it offers is that it is renewable source of energy. Therefore, technology inputs to improve the efficiency of these fuels are necessary. So to keep this in mind bio-mass converted to more useable form. Biomass is decomposed by anaerobic microorganisms to produce biogas. Biogas is a mixture of gases containing methane, carbon dioxide, hydrogen and hydrogen sulphide. Biogas plant:- 1. The plant has a dome- like structure build with cement and bricks. The lower part is the digester and the upper part has a dome with a gas outlet. On one side of the tank above the ground is a mixing tank and on the other side is an overflow tank 2. A slurry of cow-dung and water is made in the mixing tank from where it is fed into a sealed chamber in there is no supply of oxygen known as digester. 3. Anaerobic micro-organisms that do not need oxygen decompose or break down complex compounds of cow-dungs slurry. 4. It takes few days for decomposition process to be completed and generate gases like methane, carbon dioxide, hydrogen and hydrogen sulphide 5. Bio-gas is then stored in gas tank above digester from which they are drawn through pipes for use.
Advantages
a) Bio-gas is excellent fuel as it contains up to 75% of methane. b) It burns without smoke c) Leaves no residue like ash in wood, charcoal and coal burning d) Its heating capacity is high. e) The slurry left behind is removed periodically and used as excellent manure which rich in nitrogen and phosphorous. f) The large-scale utilization of bio-waste and sewage material provides a safe and efficient method of waste disposal besides supplying energy and manure.
Uses
a) Biogas is used as fuel in homes b) It is used as a fuel to run engines and water pumping sets. c) It is used to produce electricity. d) It used as a fuel in industries.

Wind energy
Moving air is called wind which is used to harness energy Wind energy is used in wind mills which converts the kinetic energy of the wind into mechanical or electrical energy. The kinetic energy of wind can be used to do mechanical work like lifting water from wells or grinding grains in flour mills. It can also be used to rotate the turbines of generators to produce electricity. To generate electricity, the rotor motion of windmill is used to turn the turbine of electric generator. A single wind mill produces only a small amount of electricity. So a large number of wind mills in a large area are coupled together to produce more electricity in wind energy farms. Traditional use
Earlier, the windmills were used to harness wind energy to do mechanical work such as lifting/drawing water from a well. Today, windmills are used to generate electricity. In windmills, the kinetic energy of wind is harnessed and converted into electricity. The rotary motion of the blades turns the turbine of the electric generator to generate electricity
Advantages
i. It is renewable source of energy. ii. It is efficient source of energy. iii. It eco-friendly. iv. It requires no recurring expenses for production

Limitations I. Wind energy farms can be established only at those places where wind blows for greater part of year. II. The wind speed should also be higher than 14 km/h to maintain the required speed of turbine. III. Initial cost is high IV. There should be some back up facilities to take care of energy needs when there is no wind. V. Establishment of it requires large amount of land. VI. Since the blades and tower are exposed to the vagaries of nature, they need a high level of maintenance.

Non-Conventional or alternative source of energy
With technology changes our energy demand is increasing day by day. So our economic increases and lifestyle develops so our demand for energy increases so we need to look for alternate sources of energy.
Solar energy
Solar energy is the energy obtained from the sun in the form of heat and light. The heat energy is used in solar heating devices like solar cooker, solar water heater, solar furnaces etc. The light energy is used in solar cells.
i) Box type solar cooker:- The box type solar cooker has an insulated box painted black inside because black color absorbs more heat. It is covered by a glass plate which allows heat to enter inside but does not allow heat to escape out. It has a concave mirror to reflect the sunlight at A fixed point so that cooking is easier. The food to be cooked is kept in containers inside the box. It can produce a temperature of 100° to 140°.
Advantage
1. It saves fuel. 2. It does not cause pollution. 3. Nutrients of food are not destroyed. 4. It is cheap. 5. Three-four items can be cooked at same time.
Disadvantage
1. It cannot be used during night. 2. The direction of reflector has to be adjusted according to position of sun. 3. On a cloudy day, it can’t be used. 4. It can’t be used for frying. 5. ii) Solar water heater:- A solar water heater has an insulated box painted black inside with a system of copper tubes. It is covered with a glass plate which allows heat to enter inside but does not allow heat to escape out. When water flows through the copper tube it absorbs heat and becomes hot.
Solar cell panel
It is easy to see that these devices are useful at certain times during day so to overcome this problem. Solar cell panel are made. Solar cell is a device which converts solar energy into electrical energy. Solar cells are made from semi-conductors like silicon, germanium, gallium etc. A single solar cell produces a voltage of about 0.5 to 1 V and produces about 0.7 W electricity. So several solar cells are arranged in a solar panel to produce more electricity. A large number of cells are combined to form solar cell panel.
Advantage and uses 1. They have no moving parts. 2. They require little maintenance and satisfactory. 3. They can be set up at remote areas. 4. It acts as a self-generating source. 5. It is eco-friendly, clean source. 6. Artificial sattlelities, space probes. 7. Radio or TV relay system 8. Traffic signal, Calculators, toys

Disadvantage 1. Special silicon needed for making it is limited. 2. Entire manufacturing is very costly. 3. Silver is needed for interconnection which further adds to the cost. 4. High cost and low efficiency.

Energy from ocean Energy from the sea is obtained in three different forms. They are Tidal energy, Sea wave energy and Ocean thermal energy. i) Tidal energy:- The periodic rise and fall of sea level due to gravitational attraction of the moon causes tides. A dam is constructed at a narrow opening between the land and sea. The movement of water during high tide and low tide can be used to rotate the turbines of generators to produce electricity. ii) Sea wave energy:- When strong wind blows over the sea it produces huge waves. The kinetic energy of the moving waves can be used to rotate the turbines of generators to produce electricity. iii) Ocean thermal energy:- There is a temperature difference between the warm surface water and the cold water at the bottom of the oceans. This difference is about 20°C. The warm surface water is used to boil liquid ammonia and the vapor is used to rotate the turbines of generators to produce electricity. The cold water from the bottom is then pumped up to cool the vapors back to liquid.
Limitations of Energy from Oceans: - The limitations of energy that can be obtained from the oceans are: a. Tidal Energy for which very few suitable sites are available for construction of dams and the power generation is intermittent and not very large. I b. Wave Energy where power output is variable and the presently available technologies are very expensive. c. Ocean Thermal Energy where the conversion efficiency is low (3% - 4%) and a lot of capital investment is required.

Geothermal energy
The deeper regions of the earth’s crust are very hot. This heat melts rocks and forms magma. The magma moves up and collects below at some places called Hot spots. The underground water in contact with hot spot gets heated into steam at high pressure. By drilling holes into hot spots the steam coming out can be used to rotate turbines of generators to produce electricity.
Merits of geothermal Energy: - 1. Geothermal energy is the most versatile and least polluting renewable source of energy. 2. It can be harnessed for 24 hours throughout the year. 3. Geothermal energy is relatively inexpensive. 4. As compared to solar energy and wind energy, the power generation level of geothermal energy is higher. 5. Geothermal energy can be used for power generation as well as direct heating. In USA, water is pumped from underground hot water deposits and is used to heat houses.
Limitations of Geothermal Energy : i. Geothermal hot spots are scattered and usually some distance away fro the areas that need energy. ii. The overall power production has a lower efficiency (about 15%) as compared to that of fossil fuels (35% to 40%). iii. Though as a whole, geothermal energy is inexhaustible, a single by ore has a limited life span of about 10 years. iv. Noise pollution is caused by drilling operations at geothermal sites

Nuclear energy
A reaction in which the nucleus of an atom undergoes a change to form a new atom and releases an enormous amount of energy is called as nuclear energy. There are two distinct ways of obtaining nuclear energy. a) Nuclear fission
b) Nuclear fusion. Nuclear Fission reaction: This type of nuclear reaction was first of all reported by Otto Hahn in 1938. He stated that when an unstable heavy nucleus is bombarded with slow speed thermal neutrons, it splits into two small stable nuclei liberates an enormous amount of heat and light energy. When uranium 235 atoms are bombard with slow moving thermal neutrons, it breaks up into two small stable nuclei of Barium and Krypton. The process also produces three neutrons and an enormous amount of heat energy and light energy. The reaction involved is shown as under:
U + n Ba + Kr + 3 n + Large amount of energy In all nuclear fission reactions, a small quantity of matter is lot i.e., the total mass of all the fission products is less than the total mass of the reactants. This lost matter gets converted into energy, which is released in any nuclear fission reaction. The energy (E) obtained due to loss of matter of mass m is given by the famous Einstein’s equation. E = mc2
Nuclear Fusion reaction: This type of nuclear reaction was first of all reported by Hans Bethe in 1939. The word ‘fusion’ means ‘to combine together’. So, nuclear fusion means combining together of two or more nuclei to form a single nucleus. Thus, a process in which two lighter nuclei fuse (combine) together to form a stable heavier nucleus with a simultaneous release of a very large amount of energy is called nuclear fusion. The energy produced in a fusion reaction is much higher than that produced in a nuclear fission reaction. Nuclear fusion takes place only at very high temperature, about 4 – 15 million degrees (4 x 10 6 0C – 15 x 106 oC). That is why nuclear fusion is also called thermonuclear reaction. Advantages of Nuclear Energy: - The advantages of nuclear energy are that: i) It produces a large amount of useful energy from a very small amount of a nuclear fuel (like uranium-235). ii) Once the nuclear fuel (like uranium-235) is loaded into the reactor, the nuclear power plant can go on producing electricity for two to three years at a stretch. There is no need for putting in nuclear fuel again and again. iii) It does not produce gases like carbon dioxide which contributes to greenhouse effect or sulphur dioxide which causes acid rain.
Disadvantages of Nuclear Energy:- i) The major hazard of nuclear power generation is the storage and disposal of spent or used fuels – the uranium still decaying into harmful subatomic particles (radiations). ii) Improper nuclear-waste storage and disposal result in environmental contamination. iii) There is a risk of accidental leakage of nuclear radiation. iv) The high cost of installation of a nuclear power plant, high risk of environmental.

Environmental consequences of the increasing demand for energy: a. The combustion for fossil fuels is producing acid rain and damaging plants (crops), soil and aquatic life. b. The burning of fossil fuels is increasing the amount of greenhouse gas carbon dioxide in the atmosphere. c. The cutting down of trees from the forest (deforestation) for obtaining fire-wood is causing soil erosion and destroying wild life. d. The construction of hydro-power plants is disturbing ecological balance 6. Nuclear power plants are increasing radioactivity in the environment.