Green Technology-III(Mains special) ; publishes about Green Technology in Q & A format. It growing relevance in real life and for UPSC exams, enables us to learn about it. Green Technology-I ,Green Technology-II


Q: What are the different sources of energy?

  • Energy comes in different forms-heat and light energy as well as mechanical, electrical, chemical and nuclear energy.
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  • We get most of our energy from sources like oil, natural gas, and coal. However, the Earth has only a limited supply of these resources, and once we exhaust them, they are gone forever.
  • Renewable energy sources are ones which don‘t run out-they can be renewed. We can keep using them and using them,  and we’ll never run out. Examples of renewable sources include wind, water power, and solar power.
  • Green technology therefore, focuses on ways to develop renewable energy sources tom meet mankind’s growing needs.
Q: What is clean energy?
  • Most of our electricity comes from power station that burn fossil fuels like coal and oil which are nonrenewable sources of energy.
  • Unfortunately,  in addition to electricity, greenhouse gases including carbon dioxide and methane are produced as well these gases pollute the atmosphere. They causes global warming and climate changes, and are generally not’ clean;
  • Renewable sources of energy like wind power, wave power, and solar power, do not pollute the air. They do not produce the greenhouse gases that cause global warming either. So these forms of energy are called clean energy.
Q: How does the wind produce clean energy?
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  • Wind is just moving air. It has huge amounts of stored energy, which is called kinetic energy.
  • This energy is harnessed by windmills to produce power. Windmills have large blades that move when the wind blows. The blades have a special curved shape, so that they can capture as much energy from the wind as possible.
  • When the wind turns the blades of a windmill, it spins a turbine inside a small generator to produce electricity. A single windmill on a farm can make only a small amount of electricity, enough to power a few farm machines.
  • To make enough electricity to serve lots of people, power companies build ‘wind farms; with dozens of windmill. Wind farms are built in flat, open areas where the wind blows at least 22.2 kilometers per hour.
  • Windmills can be seen in States like Tamil Nadu and Rajasthan, where the winds are strong and constant.
Q: Why is Hydro power cheap and safe?
  • Hydro power , or hydroelectric power is another term for energy obtained from water.
  • It is a rich source of renewable energy for countries like India and China that are blessed with plenty of big rivers.

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  • Hydro power converts the kinetic energy from falling water into electricity.
  • A hydroelectric plant does not use any more water then is produced by nature.
  • The water is held behind a dam, forming an artificial lake , or reservoir. The force of the water being released from the reservoir through the dam spins the blades of a giant turbine. The turbine is connected to the generator that makes electricity as it spins.
  • After passing through the turbine, the water flows back into the river on the other side of the dam. Over 150 countries in the world use hydro power for many purpose since it is clean, safe , comparatively cheap and renewable.
Q: What is tidal power?
  • Tides are caused in oceans and seas mostly by the gravitational pull of the moon, and to a smaller extent, by the sun’s gravity too.

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  • The part of the ocean facing the moon bulges out . the part of the ocean on exactly the opposite side of the earth bulges out too.
  • earth turns, The Ocean surface seems to rise and fall. Usually, there are two high tides and two low tides each day. There is a lot of energy in the movement of that much water. This energy can be converted into electricity by wave turbines.
  • We can use tidal energy to supply electricity to our homes and businesses. However, the costs have been too high to make it a major energy source till now.
Q: What is solar energy?
  • Solar is the Latin word for sun and the sun is a powerful source of energy.
  • We can use solar power in two different ways as a heat source, and as an energy source. We can use solar collectors for heating water and air in our homes.

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  • If you ‘ ve seen a house with big shiny panels on the roof , that family is using solar power.
  • We can also use solar energy to make electricity. The process is called photovoltaic, and it uses cells known as solar cells.
  • It is a fact that the sunlight that shines on Earth in just one hour can meet the energy demands of the world for one year!
  • Solar energy is clean, safe, and renewable but it is still expensive, and solar cells need a lot of space.
  • In the future hopefully, solar energy will become more economical and easier to harness, and convert into electricity.
Q: What is geothermal power?
  • The core of the Earth is full of heat. This heat is called geothermal energy.
  • Geothermal energy is heat generated 6437 kilometers deep inside the Earth’s core, which is made up of iron. It is seen in the from of hot springs and geysers.

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  • Geothermal energy was first used by ancient people for heating water for bathing. A geothermal power plant works by tapping into steam hot water reservoirs underground.
  • Than, the steam is used to drive an electrical generator. Many of the best location for geothermal energy are found in the ‘Ring of Fire; this is the horseshoe shaped area around the Pacific ocean.
  • Hot magma is very close to the surface of the earth here, which is why it experiences a lot of earthquakes and volcanic eruptions. This is also the reason why geothermal energy is found in abundance in this region
Q: Why is biomass a good source of energy?
  • We know that plants use up a lot of energy to make food through a process known as photosynthesis.

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  • This food is stored in plants in the form in plants in the form of chemical energy. When the plant dies, the energy is trapped inside the dead plant. This is known as biomass.
  • They energy can be released by burning. Biomass energy is renewable energy. For example, wood is biomass energy. As long as we continue to plant new trees, we will always have wood to burn, as a source of biomass energy.
  • Biomass can be converted to other usable forms of energy like methane gas, ethanol, and bio-diesel.
Q:What are Bio fuels?
  • Biofuels are fuels that we get from biomass. Bio fuels are made mostly from plants that have just been harvested.  Bio fuels can be in solid, liquid, or gaseous forms. There are three main types of bio fuels. They are ethanol, bio diesel, and bio jet fuel.

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  • Ethanol is another word for alcohol made from grains. In most countries, it is mixed with gasoline to create a blend that can be used in cars instead of petrol.biodiesel is made by refining oil, fat , or grease collected from plants and animals.
  • Biojet fuel is used in planes. Biofuels are considered renewable because they can be replenished as quickly as they are used.
  • In other words, under normal circumstances we will not run out of energy derived from biofuels. As a result, biofuels are sometimes called the fuel of the future.

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