Haryana State Board HBSE 10th Class Science Notes Chapter 14 Sources of Energy Notes.
Haryana Board 10th Class Science Notes Chapter 14 Sources of Energy
What is a Good Source of Energy
Source of energy:
A source from which useful energy can be extracted either directly or indirectly by means of a conversion or transformation is known as the source of energy. For example, sources of energy to provide us heat for cooking are LPG, kerosene, sunlight, etc.
Factors to consider while selecting an energy source:
The source of energy should be
- Availability,
- Output,
- Accessibility
- Transportation and storage and
- Economical.
Conventional (Non-renewable) source of energy:
A source of energy which we cannot regenerate or reuse once we have used it is called a conventional or non-renewable source of energy. For example, coal, petroleum and natural gas, thermal power plants, hydro power plants, bio-mass and wind energy.
Non-conventional (Renewable) source of energy:
Those sources of energy which are inexhaustible or say can be renewed are called non-conventional (renewable) sources of energy. For example, solar energy, tidal energy, wind energy, geothermal energy, etc.
Fossil fuels:
Fuels such as coal natural gas and petroleum formed in the earth crust due to decaying of plants and animal remains millions of years ago are known as fossil fuels.
Disadvantages of fossil fuels:
- Produces smoke
- Cause severe air pollution,
- Causes acid rain.
- Causes global warming.
Thermal power plant:
Thermal power plant is a set-up which converts heat energy into electrical energy on a large scale basis.
Hydropower plant:
Hydropower or hydroelectric plants use the potential energy of water stored at height (in dams) and the kinetic energy of the falling water for generating electricity. The power produced is called hydroelectricity or hydel electricity.
Disadvantages:
- Dams can be constructed only in some hilly areas,
- People living in low areas have to be relocated.
- Large ecosystems get destroyed
- Methane gas gets produced in large quantity.
Biomass:
The waste material from plants or animals such as cattle dung, dried leaves, etc. which is not used for food or feed is called biomass.
Biogas:
The gas prepared by decomposing cow dung, plant residue such as dead plants, dried leaves, residue obtained after harvesting a crop, vegetable waste and sewage in a pit is called biogas or gobar gas.
Advantages:
- An excellent fuel used for cooking and lightening
- Burns without smoke and leaves no residue
- High thermal capacity
- The slurry is an excellent manure
Biogas can also be used for lightening the villages.
Wind:
Moving air is called wind. Wind possesses kinetic energy. This kinetic energy can be used to do work or obtain electricity through a machine called wind mill.
Advantages:
- Does not cause any pollution
- It is renewable,
- Does not cause any recurring expense.
Limitations:
- Wind farm can be established only at those places where wind blows for most of the year that too with a minimum speed of 15 km/h
- Requires power back-up facility
- Required large area,
- Initial set-up cost is quite high,so is the maintenance.
Alternetive or Non-conventional Sources of Energy
Alternate (non-conventional) sources of energy:
Sources of energy which we have not yet started using on a regular and routine basis are called non-conventional sources of energy. Example: Solar energy, oceanic energy, geothermal energy and nuclear energy.
Solar energy.
The energy obtained from the sun is called solar energy. This energy is available in two forms namely, light and heat.
Solar appliances and their uses:
| Solar appliance | Use |
| 1. Solar cooker | To prepare food such as rice, dal, pulses and vegetables. |
| 2. Solar water heater | For heating water in houses, hotels, etc. |
| 3. Solar cells | In artificial satellites, calculators, toys, etc., In remote areas in street lights and in running radio and T.V., For operating traffic signals and in research centres, In cars at experimental levels. |
Energy from sea:
Tidal energy:
The level of ocean water rises and falls due to the gravitational pull of moon on the earth. The difference ¡n the tides give us energy which is called tidal energy.
Wave energy:
The winds blowing over ocean produces waves. These waves possess large amount of kinetic energy. Several devices have been developed to trap wave energy for rotating the turbine and hence producing electricity.
Ocean Thermal Energy Conversion (OTEC):
The energy available due to the difference in the temperature of water at the surface of the ocean and at deeper levels of the ocean is called Ocean Thermal Energy (OTE). The plant set-up to harnass this energy is called Ocean Thermal Energy Conversion (OTEC) Plant.
Geothermal energy:
The deep interior region of the earth where magma is found is very hot. The energy utilized from this heat is called geothermal energy. At some places, steam and hot water ooze out on their own through cracks of the rocks. Such sites serve as hot water springs or natural geysers.
Nuclear energy:
- When the nucleus of a heavy atom (such as uranium, plutonium or thorium) is bombarded with low-energy neutrons, it gets split into lighter nuclei. This process is called nuclear fission.
- During the splitting of nucleus, tremendous amount of energy is released. This energy is called nuclear energy.
Advantages:
- Produces 10 million times the energy produced by the combustion of an atom of carbon from coal,
- The nuclear fuel can itself go on chain reaction and release energy at a controlled rate.
Limitations:
- The biggest problem is the storage and disposal of used nuclear fuel.
- In case of accident if the radiations leak, they can cause very large and widespread effect.
- The installation cost is very high.