In basic terms, “conventional and non-conventional” sources of energy give an idea about how it is easier to reach the resource at present and how feasible it is in terms of economic viability. There are a lot of natural resources present around us. Some are present beneath the Earth (fossil fuels, geothermal energy), some are on the Earth (ocean, river), some are above the Earth (wind) and some are present far away from the Earth (The sun). But for the past many years, we are using some particular resources (like petro, diesel, and gas) and more advanced mechanisms are available to extract energy from these sources. Therefore, these sources of energy are known as conventional sources of energy. These sources are very limited in nature. On the other hand, some sources of energy are available for a very long time and can provide an unlimited amount of energy. Unfortunately, we do not have enough advanced technology to extract energy from these sources. These sources of energy are non-conventional sources of energy.
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The resources, which are locked in the dead organic materials beneath and far away from the Earth, found naturally are known as natural sources of energy.
The natural sources of energy are divided into two categories,
The energy sources that are present for a long time found naturally on or beneath the Earth and take a long time to produce or replenish are known as conventional sources of energy. Generally, these are also non-renewable energy sources. The conventional sources of energy are again divided into two categories, commercial and non-commercial energy sources.
Commercial energy sources: To get energy from these kinds of sources, we need to pay for it.
The consumption price depends on various factors like demand and supply, availability, feasibility etc. A few examples are,
(a) Electricity: It is the most common and essential form of energy which we use in our daily life. It runs many home appliances like fridges, bulbs, washing machines etc, also used in commercial buildings and in production units. Electricity is produced by various commercial energy sources in power plants like nuclear power plants, hydroelectric power plants, and thermal power plants.
(b) Coal: It is a type of fossil fuel which is present beneath the surface of the Earth and was formed by decomposed organic materials due to the high compression and temperature due to Earth’s layers. It takes millions of years to form coal which we use. Therefore it is a non-renewable energy resource.
(c) Natural gas and oil: These are also obtained from fossil fuels and are present beneath the surface of the Earth and formed from decomposed organic materials. They are in such form because of the high compression and temperature of the Earth’s layers. Natural gas and oil also take a very long time to produce but can be used instantly therefore these are also known as non-renewable energy resources.
Non-commercial energy sources: The energy resources which are generally available are free to use. Examples are firewoods, cow dung, and straw. Firewoods are obtained from the trees and plants, dung is obtained from animal wastes and straw is obtained from the crop plants like wheat crops, rice crops etc.
The natural resources that can produce useful energy continuously for a long period of time and are available again and again for use even after it is exhausted are known as non-conventional sources of energy or renewable resources of energy. Some types of non-conventional sources of energy are; sunlight, wind, water flow, and ocean.
(a) Solar energy: The energy produced by the Sun is referred to as solar energy. It is formed due to nuclear fission and fusion inside the Sun. This energy travels in the form of radiation (electromagnetic waves). This energy is collected by some photovoltaic cell panels which absorb the solar energy and convert it into electricity that can be used for home appliances. Solar heating panels are used to heat the water in the solar heater.
(b) Wind: When we talk about wind energy then it means that the wind speed should be high enough to produce a considerable amount of useful work. This kind of wind energy is usually available near the coastal regions or near the mountains where high wind flow is available at a constant rate. Big turbines, called wind turbines are installed at such sites to tap this wind energy which drives these turbines and as result, electricity is generated.
(c) Tidal energy: We know the tides are created in the ocean due to the rotation of the Earth and the attraction between Earth and the moon. Tides are nothing but the rise and fall of the water level in the ocean. We can observe it easily on the shores. The tidal energy is captured by forming narrow dams at the narrow entrances of rivers. During high tides and low tides, the motion of the water column is used to rotate the turbines that produce electricity.
(d) Biomass energy: Biomass energy is extracted from biological materials where biological materials are formed from living organisms and plants. In the biomass power plant, biomass is burnt into a combustor in order to produce heat which will be further converted into mechanical energy in order to generate electricity. Biomass can also be converted into other forms of energy like fuels used in transportation, biodiesel or methane gas depending on the requirements.
(e) Geothermal energy: As we know that the temperature increases as we move inside the Earth's layers. This high temperature is the thermal energy source. Potential sources can be hot springs and volcanoes which contain a very high amount of heat. This kind of energy is known as geothermal energy. This energy can be extracted and can be used to generate electricity. In Himachal Pradesh and Ladakh, geothermal power plants are located.
(f) Hydro energy: This energy is generally available in flowing rivers. A dam is formed to store the water of the river at some convenient location. This stored water contains the potential energy which can be converted into kinetic energy by giving a narrow passage to the flow. Thus we get a water stream with high-speed that drives large turbines to produce electricity.
Conventional sources of energy
Non-conventional sources of energy
These are already available in nature but can not be used after they are exhausted.
These are also already available in nature but can produce energy continuously at an almost constant rate.
They are limited in nature.
Since these are continuously replenishing energy resources and will be exhausted after millions of years. Therefore we can extract an unlimited amount of energy from them.
Easily available in our daily life.
For now, these sources are alternate sources of energy.
Produce a lot of pollution which is harmful to both humans and nature.
By-products are very less or negligible, hence these are good resources of energy.
Some energy resources are available for both domestic uses and for industrial uses.
For now, these are used majorly for domestic purposes.
Fossil fuels and nowadays, nuclear fuels are some of the examples of conventional sources of energy.
Sunlight, ocean tides, wind, geothermal energy and hydro energy are some of the examples of non-conventional sources of energy.
Q1. Write the working of a thermal power plant.
A. A thermal power plant is a power generating facility that produces electric power. In a thermal power plant, a fossil fuel (coal or natural gas) is burnt to produce thermal energy (as heat). This thermal energy is converted into the form of high-pressure steam. It is then converted into mechanical energy by steam turbines. Hence the electricity is produced.
In a thermal power plant, the fuel (coal) is burnt into a furnace to produce heat. This heat is used to boil the water, present in a boiler. As a result, steam is produced in the boiler. As the temperature increases, steam pressure also increases and when it passes through the narrow tubes, it flows at a high speed. Now, this high-speed steam is passed onto the steam turbines and the turbines start rotating. An electric generator is connected to the steam turbine which converts this mechanical energy from the turbine into electricity. Meanwhile, steam passing through the turbine loses its kinetic energy and temperature. This steam is then again converted into the water in a condenser. In this condensing process, steam loses heat in the surrounding. Then the water is sent to the cooling tower where the water temperature is cooled down and is reused again for the next cycle.
Q2. Explain the working of the nuclear power plants.
A. The nuclear power plant basically works on the principle of nuclear fission in which the radioactive energy source like uranium is used as the working fuel. Nuclear fission is a chain reaction in which the nucleus of the heavier atoms U235 is split into smaller ones with the release of a large amount of energy in the form of heat. This energy is then used to produce electricity in a safe and shielded facility called nuclear power plant.
Generally, uranium-235 () is used as a nuclear fuel which is in the form of rods. The core is typically constructed by a thick wall of cement and steel which is used to cover and protect the outer environment and human lives from the radioactive radiation produced during the nuclear chain reaction. The core surrounds the nuclear reactor and the steam generator. Moderator which is generally made up of heavy water or graphite is used to slow down the high-speed neutrons during the chain reaction in the reactor. Control rods are used to control the chain reaction by increasing or decreasing the neutron flux in the reactor. Boron, cadmium or hafnium are used to make the control rods. A coolant is used to collect the heat generated during the chain reaction. Coolant is fluid (water or CO2) that flows in the tube and passes through the steam generator. The energy collected from the nuclear reactor by the coolant is then transferred to the water present in the steam generator which produces steam in it. High-pressure steam is then passed through the narrow tube which increases its speed and this high-speed steam is then imparted to the turbine in order to produce rotational mechanical energy. An electric generator is connected to the turbine which converts the mechanical energy into useful electrical energy.
Q3. Draw a pie chart for fossil fuels that shows the use of fossil fuels in India and across the world?
As seen from the above pi-chart, fossil fuels are majorly used for industrial purposes and are almost equally used for domestic, transportation and other purposes.
Q4. What are the advantages of non-conventional energy over conventional energy?
(1) Regarding its future and its use in science and other applications, there is a vast area of research in the nonconventional energy source sectors.
(2) Non-conventional energy, often known as renewable energy, is a naturally available source that has a big impact on the local and regional economic sectors even in the remotest parts because non-conventional energy is available for a very long time and once the power generation facilities are installed, it can produce useful work for a long time without spending much work on it.
(3) In addition to helping to reduce pollution and create a sustainable environment, renewable energy has a low energy density. So it has less potential for any accident.
(4) Non-Conventional energy-based power plants don't have very high fuel costs, making them considerably more affordable to people and businesses.
Q1. What do you mean by energy?
A. Energy is known as the capacity of a machine or a system to perform work. Now to get useful work from a machine, we need to provide some energy into it. This energy could be electrical, mechanical, thermal, nuclear, etc.
Q2. What are the qualities that exist in a good source of energy?
A. A good source of energy should have at least the following basic qualities:
Q3. Why are non-conventional sources of energy becoming important to us?
A. Since the conventional sources of energy are mostly non-renewable in nature and it takes a very long time to produce, these will be completely exhausted after some years. So we need an alternate source of energy that can come from non-conventional sources of energy and renewable in nature because non-conventional sources are available for millions of years that can produce an unlimited amount of energy which we can use to produce useful work from it. Therefore non-conventional sources of energy are now becoming very important to us and in the future for sustainable development, these will become the main source of energy.
Q4. What are the main sources of energy that are available in India at present?
A. At present, coal, oil and natural gas are the main sources of energy that are available in India. Almost 60% of the total energy comes from non-renewable energy resources and about 40% of the total energy is produced from renewable energy resources.