Sources of Energy Class 10 Notes CBSE Science Chapter 14 [Free PDF Download]

Introduction

Energy has various forms and can be converted from one form to another. A source of energy that produces energy in a convenient form for a long span of time can be considered to be a good source of energy.

Topics Covered under the Chapter

• Introduction 

• Qualities of a Good Source of Energy

• Sources of Energy

• Conventional Energy Sources

• Thermal Power Plants

• Hydro Power Plants

• Biomass

• Wood

• Charcoal

• Cowdung

• Bio Gas

• Wind Energy

• Alternate Sources of Energy

• Solar Energy

• Solar Cell

• Solar Cooker

• Energy from the Sea

• Geothermal Energy

• Nuclear Energy

• Nuclear Fusion

• Environmental Consequences

Disadvantages of Burning Fossil Fuels

• Combustion of Fossil fuels produces byproducts that cause air pollution.

• Acid rain and the greenhouse effect are caused by the burning of coal and petroleum that produce harmful oxides of sulphur, carbon, and nitrogen.

• Global warming is caused by gases that are emitted by the burning of fossil fuels.

Nuclear Fission

Nuclear fission is the procedure where a heavy atom, like uranium or plutonium, is bombarded using neutrons, which splits this atom in order to give lighter nuclei. Doing this releases a tremendous amount of energy. 

Nuclear Fusion

• Fusion refers to the combination of lighter nuclei for producing a  heavier nucleus, which is usually hydrogen or hydrogen isotopes, for creating helium.

• This releases a huge amount of energy and the deficit of mass between the product and the reactants is given by Einstein’s equation, which is E=mc2.          

Environmental Consequences

The exploitation of any form of energy will eventually disrupt the balance in the environment in some way or another. No source of energy is perfectly free of pollution. It will cause some disturbance no matter what and will lead to heavy damage to the Earth in the long run. An instance can be solar cells, which are practically pollution-free. However, their assembly will inflict some kind of damage to the environment. 

Characteristics Of A Good Fuel:

• High calorific value

• Less smoke

• Less residue after burning

• Easy availability

• Inexpensive

• Easy to store and transport

Fossil Fuels:

• Plant and animal remains were buried under the earth and subjected to high temperature and pressure conditions millions of years ago, resulting in the formation of lava flows. 

• For example, coal, petroleum, and so forth.

• These fossil fuels are non-renewable energy sources that contribute to pollution in the environment.

Thermal Power Plants:

• Thermal electricity is generated from coal, petroleum, and natural gas.

• The transmission of electricity is very efficient.

• The steam generated by the combustion of fossil fuels powers the turbine, which generates electricity.

Hydropower Plant:

• It is the most common form of renewable energy, derived from water falling from vast heights.

• It is a non-polluting and clean source of energy.

• Dams are built to catch water flowing via high-altitude Rivers. There is a lot of potential energy in the stored water.

• When water falls from a height, potential energy is converted to kinetic energy, which rotates the turbines to produce electricity.

Disadvantages Of Hydro Power Plant:

1. Construction is extremely costly.

2. Dams are not feasible on all riverbeds.

3. Submergence of large areas of human settlement and agricultural lands.

4. People are confronted with social and environmental issues.

Non-Conventional Sources:

1) BioMass:

a) It is the source of our country's routinely used fuels. 

b) Cow dung cakes, firewood, coal, and charcoal, for example.

c) Biogas is a combination of gases created when biomass decomposes in the absence of oxygen (Anaerobic Respiration).

d) Biogas is primarily composed of methane.

e) Animal dung, sewage, agricultural leftovers, vegetable wastes, chicken droppings, and other wastes are utilised in Biogas plants to make Biogas.

2. Wind Energy:

a) Mechanical and electrical energy can be converted from it.

b) Wind turbines, which are used to lift water, use kinetic energy from the wind.

c) Benefits: 

i) Environment friendly

ii) Renewable

d) Disadvantages:

i) Wind speed is not always consistent.

ii) Requires a big space to construct a series of wind turbines.

iii) A significant quantity of capital is required.

iv) The output is lower than the investment.

3. Solar Energy:

a) Solar cells can convert solar energy into electricity (photovoltaic cells).

b) Photovoltaic cells use silicon solar cells to convert solar radiation into electricity.

c) A solar panel is made up of solar cells arranged on big flat sheets.

d) Solar water heaters, Solar furnaces, etc. are the other solar devices.

e) Solar cookers have a big glass plate and are painted black on the outside to capture solar energy through the greenhouse effect.

f) Advantage of Solar Cookers:

1. Eco friendly

2. Renewable

3. Used in rural areas.

4. Retains all the nutrients in food due to slow cooking.

g) Disadvantages Of Solar Cooker:

1. Silicon cells are not cheap.

2. Solar radiation is not uniformly distributed across the Earth's surface.

3. Not suitable for usage at night or on foggy days.

4. Cannot be used to make fried chapattis because they require a temperature of at least \[140{}^\circ C\]. (Only a solar cooker can reach a maximum temperature of \[100{}^\circ C\] .)

Geo-Thermal Energy:

• Geothermal energy is a type of energy that is derived from the sun's heat.

• When this heat melts the rocks, magma is created. 

• Magma is the term for molten rocks and hot gases.

• Magma collects at various depths under the earth's surface. These are known as "Hot Spots" because when underground water comes into touch with them, it turns into steam, which may be used to generate power.

• Advantages Of Geothermal Energy:

• Renewable

• Inexpensive

• Disadvantages Of Geothermal Energy:

• Very few sites are available for harnessing energy.

• Expensive

Nuclear Energy:

• Nuclear energy is the energy released when the nucleus of an atom of a substance undergoes changes.

• It is utilised as a source of heat and as a fuel for marine boats.

• Advantages Or Nuclear Energy:

• An alternative source of energy due to depletion of fossil fuels.

• A significant amount of energy is released from a small amount of fuel.

• Disadvantages Of Nuclear Energy:

• Risk of nuclear waste leakage

• Expensive nuclear plant construction

• Pollution of the environment

Energy From The Sea:

• Tidal Energy in India: Gulf of Kutch, Gujarat, and West Bengal – 

• Relies on tidal action to control the rise and fall of sea level.

• Dams are built across a narrow stretch of sea, and a turbine converts tidal energy to electricity.

• The main disadvantage for using this is that there is no consistent tidal action.

• Wave Energy:

• Turbines are rotated by the kinetic energy of sea waves.

• These turbines produce electricity.