Telangana TSBIE TS Inter 1st Year Environmental Education Study Material 11th Lesson Conventional and non-Conventional Sources of Energy Textbook Questions and Answers.
TS Inter 1st Year Environmental Education Study Material 11th Lesson Conventional and non-Conventional Sources of Energy
Essay Questions
Question 1.
Explain the sources of energy.
Answer:
I. Conventional Sources of Energy :
(Non-Renewable) Conventional Energy refers to energy that is obtained from any source that has been in widespread use for a long time. Fossil fuels and traditional biomass are the most widely used conventional source of energy. Coal, petroleum and natural gas are examples of fossil fuels. Kerosene and propane are derivatives of fossil fuels. Traditional biomass refers to wood and other organic matter.
Till the beginning of the nineteenth century nearly all the energy in the world was produced by the burning of wood. Less than 2% was derived from coal, produced and used mostly in the U.K. Oil consumption began in the 1870s. By the end of the nineteenth century, coal consumption increased greatly. It accounted for half the global energy.
Fossil fuels are formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earths crust over millions of years. When fossil fuels are burnt they produce a lot of energy. Although human beings used fossil fuels in ancient times, the large scale extraction of these fuels began only during the Industrial Revolution. Within a short period of two hundred years we have consumed so much fossil fuel that the available deposits have been practically exhausted.
It is estimated that we will run out of oil, gas and coal by the end of this century. New reserves of fossil fuels are difficult to find and are much smaller than the ones found in ihe past. For this reason fossil fuels are considered Non Renewable sources of energy. They are a finite resource and cannot be replenished as they take millions of years to be formed.
Advantages of Conventional Sources of Energy :
- The technology to harness energy from fossil fuels is well developed.
- Fossil fuels are cheap and reliable sources of energy.
Disadvantages of Conventional Sources of Energy :
- Fossil fuels contain large amounts of carbon and contribute to global warming. They are not green sources of energy and so, pollute the environment.
- Fossil fuels are nomrenewable sources of energy. The existing reserves will almost certainly be exhausted well before the turn of this century.
II. Non-Conventional Sources of energy (Renewable) :
As conventional sources of energy are exhaustible and also cause pollution, scientists have been trying to find alternative sources of energy which can be easily replenished and do not pollute the environment. Many non conventional sources of energy have been developed during the last few decades. Solar energy, wind energy, nuclear energy, biomass energy, geothermal energy and tidal energy are examples of non conventional energy. While it is true that some of these sources, such as wind energy and biomass energy, were harnessed even in ancient times, the large scale exploitation of these resources in a systematic manner started only towards the end of the nineteenth century.
Advantages of Non – Conventional Sources of Energy :
a) Renewable Resources :
The most promising aspect of non – conventional sources of energy is that they are inexhaustible. Solar energy and wind energy can be harnessed as long as the Sun exists. The vast oceans are a perennial source of wave and tide energy. Uranium, needed for nuclear energy, may be exhausted in 200 years but if extracted from sea water, will last for 60,000 years. Non conventional sources of energy are, therefore, called Renewable sources of energy as they are constantly being replenished and will never get depleted.
b) Non Polluting :
Another remarkable feature of non conventional sources of energy is that they are clean and do not pollute the environment. No waste is produced. Biomass energy releases carbon, no doubt, but the carbon is already present in the organic waste that is burnt to get energy.
c) Cost Effective :
Non-conventional sources of energy are becoming increasingly cost effective with each passing day. Rapid improvements in technology are enabling developing countries to leapfrog and remain on a par with developed countries.
Disadvantages of Non – Conventional Sources of Energy :
a) Safety issues :
Accidents in nuclear power plants can cause leakage of radioactive material. This can have disastrous consequences not only for the workers involved but for residents living several miles away from the plant. The effects of radioactivity on human beings can linger for decades, affecting future generations. The ecosystem too is destroyed.
b) Initial costs of installation of power plants may be high.
Question 2.
Explain the types of Non – Conventional sources of energy.
Answer:
1. Solar Energy :
The Sun is a powerful source of energy. The energy provided by the Sun to the Earth in one hour can meet the energy needs of the entire globe for a year. At present we are able to harness only .0001 % of that energy. Rapid strides in technology are enabling us to transform solar power into thermal and electrical energy efficiently and at reduced costs. The International Energy Agency estimates that by 2050 the production of solar energy will account for nearly a quarter of the world’s total energy use.
Solar power harvests the energy of the Sun by using collector panels to create conditions that can then be turned into a kind of power. Large solar panel fields are often used to gather enough power to charge small substations. Many people use solar systems for heating their house in winter and cooling it in summer. Hot water too is easily obtained.
Advantages of Solar Energy :
- Solar energy is a clean and renewable energy source.
- Once a solar panel is installed, solar energy can be produced free of charge.
- The Sun is practically an infinite source of energy as it will exist for another 5 billion years. In contrast, it is estimated that the world’s oil reserves will last only for another 30 to 40 years.
- Solar energy causes no pollution. Solar cells do not produce emissions or noise.
- Very little maintenance is needed to keep solar cells running.
Disadvantages of Solar Energy :
- The initial cost of setting up solar panels is quite high.
- Solar cells can generate electricity only during daylight hours.
- Solar energy production is not feasible in geographical areas which receive less sunlight.
- Pollution levels in the air can affect the efficiency of solar panels.
- Solar panels are heavy, so roofs of houses where they are being installed must be strong.
India has set a target of achieving 100 GW of solar power by 2022. Four of the largest solar plants in the world are in India, including the second largest solar park in the world at Kurnool, Andhra Pradesh. The world’s largest solar power plant, Bhadla Solar Park, is being constructed in Rajasthan.
2. Wind Energy :
Wind energy is a form of solar energy. Wind turbines, like windmills, are mounted on towers and convert the kinetic energy in the wind into mechanical power. A generator then converts the mechanical power into electricity. Wind energy harvesting has grown by 25% every year over the last two decades. By 2030 wind power is expected to supply nearly 20% of the world’s electricity.
Advantages of Wind Energy :
- Wind is a clean, non polluting source of energy.
- It is an inexhaustible source of energy as it originates in the Sun.
- It is cheap. The cost of wind power is rapidly decreasing and has fallen by more than 50% over the last few years. In 2018 it fell to a record low of ₹ 2.43 per unit in India.
- Wind turbines are space efficient. As they do not occupy much space, there is practically no disruption in the usage of the open land in which they are located.
- Maintenance costs are low.
Disadvantages of Wind Energy :
- Wind energy is a fluctuating or intermittent source of energy as wind conditions do not remain steady in a place. Wind energy needs to be stored for full utilization.
- Initial building and installation costs of wind turbines are high.
- Wind turbines generate noise though newer technology is making them much quieter. A wind turbine located 300 meters from a house generates just about the noise of an air conditioner.
- It has been claimed that wind turbines are a threat to wild life, especially bats, but these claims are not substantiated.
Denmark is regarded as the birthplace of wind energy harvesting. The Gansu wind farm in China is the world’s largest wind farm, with a target of 20000 MW by 2020. Today wind energy is India’s biggest source of renewable electricity, accounting for nearly three times as much generating capacity as solar. The Muppandal wind farm in Tamilnadu is the largest wind farm in India.
3. Geothermal Energy :
Geothermal energy is the energy that is produced from beneath the Earth. It is clean, sustainable and environment friendly. High temperatures are produced continuously inside the Earth’s crust by the slow delay of radioactive particles. Hot rocks present below the Earth heat up the water that produces steam. The steam is then captured and is used to move turbines. The rotating turbines power the generators.
Geothermal energy can be used by a residential unit or on a large scale by an industrial application. It was used during ancient times for bathing and space heating. The biggest drawback in using geothermal energy is that it can be produced only at select sites throughout the world. The largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California, United States. Indonesia, Iceland, and Philippines are countries which have very large geothermal plants. The first geothermal plant of India is located in Balrampur district in Chhattisgarh and will become operational shortly.
4. Hydrogen Energy :
Hydrogen is one of the most common elements available on Earth. It is an energy carrier, not an energy source. Hydrogen can store and deliver usable energy, but it does not typically exist by itself in nature and must be produced from compounds that contain it. Once hydrogen is separated from compounds such as water, it can be used as a fuel for generating electricity. Hydrogen is a tremendous source of energy and can be used as a source of fuel to power ships, vehicles, homes, industries, and rockets. It is completely renewable, can be produced on demand from organic waste or water and does not leave any toxic emissions in the atmosphere. However, the cost of producing hydrogen energy is very high. Japan, Germany, Iceland, and U.S.A are countries which are in the forefront in the field of hydrogen energy.
5. Tidal Energy :
Tidal energy uses the rise and fall of tides to convert kinetic energy of incoming and outgoing tides into electrical energy. It is dependent on the gravitational force of the Earth and the moon. Tides are produced when there is increased height of water levels in the ocean. The generation of energy through tidal power is mostly prevalent in coastal areas. Huge investment and limited availability of sites are the major drawbacks of tidal energy. Tidal energy is one of the renewable sources of energy. Large amounts of energy are produced even when tides move at a low speed. South Korea has the largest tidal power plant in the world. France, U.K. and Belgium are other countries which have such plants.
6. Wave Energy :
Wave energy is produced from the movement of waves that are produced in the oceans. Wave energy is renewable, environment friendly and causes no harm to the atmosphere. It can be harnessed along the coastal regions of many countries and can help a country to reduce its dependence on foreign countries for fuel. However, wave energy has its disadvantages. It can damage the marine ecosystem and can also be a source of disturbance to private and commercial vessels. It is highly dependent on wavelength and can also be a source of visual and noise pollution. Sweden, Portugal, Spain and U.K. are some countries which produce wave energy.
7. Hydroelectric Energy :
Hydroelectric energy is produced when the power of moving water is harnessed to produce electricity. The power of moving water has been harnessed for centuries. Initially it was used to run grain mills. Today hydroelectric power is the most widely used non conventional type of energy in the world. It represents about 17% of total electricity production. China is the largest producer of hydroelectricity, loilowed by Canada, Brazil and the united States.
Advantages of Hydroelectric Energy :
- Hydroelectric energy is a clean fuel source as it is produced from water.
- Hydropower plants do not pollute the air, unlike power plants that burn fossil fuel.
- These plants are safe when compared to nuclear plants.
- They are renewable sources of energy as electricity can be produced as long as water is available.
Disadvantages of Hydroelectric Energy :
- Hydroelectric energy can be produced only in regions where there is ample water.
- It is not possible to generate hydroelectricity in the event of drought.
- The initial cost of building dams and hydroelectric power plants is high.
- The construction of dams can have a negative impact on the ecology. Thousands of people are displaced and lose their livelihood. The breeding and migratory patterns of fish, like salmon, are affected. Sediments that would go down-stream and replenish the soil are held back by dams. Now-a-days, therefore, environmentalists put up stiff opposition when hydroelectric projects, such as the Narmada Valley Project, are constructed.
8. Biomass Energy :
Biomass energy is produced from organic material that comes from plants and animals. Biomass includes crops, plants, trees, yard clippings, wood chips and animal wastes. Wood accounts for 44% of biomass energy. Chlorophyll present in plants captures the Sun’s energy by converting carbondioxide from the air and water from the ground into carbohydrates through the process of photosynthesis. When the plants are burned, the water and carbondioxide are again released back into the atmosphere. Biomass energy is used for heating and cooking in homes and as fuel in industrial production.
Advantages of Biomass Energy :
- Biomass energy is a renewable source of energy as biomass plants utilize leftover wood.
- It is an alternative to fossil fuels.
- It does not produce carbon. It merely releases the carbon that is already there in the plant or animal waste. In that respect it differs from fossil fuels which generate carbon when burnt.
- Organic waste of plants and animals is readily available in abundance.
- Instead of being thrown in landfills and polluting the environment, organic waste is utilized to get energy.
- Different products can be created from different kinds of organic matter. Methane, biodiesel and other biofuels can be produced. Heat and electricity can be generated with the help of turbines.
Disadvantages of Biomass Energy :
- Biomass energy is not a clean energy as pollution is created from the burning organic waste. The pollution may be as bad as that caused by the burning of coal.
- In addition to plant and animal waste, healthy trees are often cut and used for the purpose of producing biomass energy. This can lead to deforestation, displacement of people and destruction of the habitat.
- Biodiesel products like ethanol are inefficient fuels compared to gasoline. The long term use of ethanol may be harmful to combustion engines.
- Biomass plants require a lot of space and add to urban congestion when located in cities.
- The cost of setting up biomass plants is very high.
9. Nuclear Energy :
Nuclear energy is power released through specific nuclear reactions. This power is then converted to electrical power. There are about 30 countries which produce nuclear power. U.S.A produces more electricity through the use of nuclear power than any other nation. It is followed by France, Russia, South Korea, Germany and China. France derives more than 75% of its energy needs from nuclear power.
Advantages of Nuclear Energy :
- Nuclear energy is cheap.
- It is a source of clean energy as relatively low amounts of carbon dioxide are released during the nuclear reactions.
- The technology is readily available.
Disadvantages of Nuclear Energy :
- There are major concerns about safety. An accident in a nuclear plant can cause leakage of radioactive material which would have disastrous and long-lasting consequences on human beings as well as on the environment. The nuclear plant accident in Fukushima, Japan in 2011 is one such example.
- Nuclear waste that is generated must be disposed of with extreme care.
- Nuclear plants can become targets for terrorists.