Chapter 31B Energy Conservation

NIOS Class 12 Environmental Science Chapter 31B

INTEXT QUESTIONS 31.1

1. Mention two most important impacts of energy use on the environment.

Ans: Depletion of energy; emission of greenhouse gases due to the burning of fossil fuels.

2. Mention four important activities which you require energy in your daily life.

Ans:  Cooking, heating and cooling of houses, TVs and computers and electrical gadgets. (Any other)

3. Which is the most important input or factor required for economic growth in today’s world?

Ans: Population

INTEXT QUESTIONS 31.2

1. Name any one purpose for which the community may install a solar pump.

Ans: Water purification and irrigation.

2. Why should we replace the ordinary bulbs in our house with CFL bulbs?

Ans: They use much less electricity and last longer.

3. Why should there be regular monitoring and an energy audit at work workplace?

Ans: To reduce energy consumption/ to conserve energy.

4. What is carpooling, and how can carpooling help in conserving petrol?

Ans: Carpool is sharing cars for going to workplaces. Much petrol is wasted when each person takes their own car to travel to the same place.

INTEXT QUESTIONS 31.3

1. Expand CFL.

Ans: Compact Fluorescent Lamp

2. Name the equipment which uses wind as a source of energy at Auroville in Pondicherry.

Ans: Wind pump

3. What is the concept of an energy-efficient town?

Ans: A township whose constructions are eco-friendly and whose inhabitants are eager to conserve energy resources.

INTEXT QUESTIONS 31.4

1. What is the role of energy auditing?

Ans: Systematic approach for monitoring industrial energy consumption and identifying sources of wastage.

2. Give one limitation for each of the following renewable sources of energy: (i) hydel power, (ii) geothermal energy, (iii) nuclear energy

Ans:

• (i) Ecosystems/human settlements disturbed/ habitat loss/ biodiversity loss/ high developmental cost (any one)
• (ii) Smelly H₂S released/ pipelines corroded/ toxic minerals released. (anyone)
• iii) High cost of construction of nuclear plant/ fear of security and nuclear accidents/ problem of safe disposal of nuclear waste. (anyone)

3. Give one advantage for each of the following renewable sources of energy: (i) solar, (ii) biomass, and (iii) wind.

Ans:

• (i) Environment-friendly, cheap, and so popular in underdeveloped and developing countries
• (iii) No pollution, available for free.

TERMINAL EXERCISE

1. What is energy conservation, and how can it be conserved at the household level?

Ans: Effective use of fossil fuels and energy from different sources to prevent unnecessary wastage is known as energy conservation. The steps in developing an energy conservation plan for our home are 

• (1) Identify the problem areas where energy is being lost or inefficiently used. 
• (2) To prioritise the problem areas according to how much energy is being lost or inefficiently used 
• (3) Systematically correct the prioritised problems according to the limits of our household energy improvement budget.

2. How is energy conservation possible while constructing buildings? Explain with the example of some energy-efficient buildings.

Ans: 

Eco house, a residential building and was constructed in mid mid-seventies. It was equipped with a solar cooker and a multifeed biogas plant. Rainwater harvesting is also used in this house. A roof-mounted wind generator was also contemplated but not installed. The following technologies were used in this house-

• Rainwater harvesting with an underground cistern.
• Roof-integrated solar water heater.
• Window-mounted retractable solar cooker.
• Multifeed biogas plant, usable as a septic tank, if required.
• Three different types of experimental roofs (hollow concrete tiles, Prefab brick jack arches, Madras terrace roof).
• Design for Ventura (ventilation via inner courtyard).

3. What are energy-efficient devices? Give some examples of such devices.

Ans: Energy-efficient devices consume reduced energy or use the available energy effectively to reduce overall power consumption. 

• Compact Fluorescent Lamps (CFLs) replaced incandescent bulbs. 
• Open utensil cooking has been replaced with pressurised steam cooking and, of course, solar cooking. 
• Other energy-efficient devices which can be used for energy conservation are a diamond hot plate, a PRP bullock cart, tubelight with an electronic ballast device, which helps in reducing energy consumption by limiting the amount of electric current in an electric circuit.

4. How can energy-efficient towns be designed?

Ans: The design of the town should be such that developmental densities should be highest towards the centre of the town, which is served by municipal water and sewer. 

• Outlying areas should have much less construction.
• A township can be oriented towards becoming eco-friendly only with the cooperation of the inhabitants. 
• A township may have structures of eco-friendly architecture, but unless the inhabitants resolve and practice energy conservation and an eco-friendly way of life, the purpose of an energy-efficient town would be defeated. 
• Education, eco-friendly behaviour and ecologically sound infrastructure can truly create energy-efficient green towns.

5. Define the concept of energy auditing. How can it be helpful in energy conservation?

Ans: Energy auditing is a systematic approach to monitor industrial energy consumption and to find out the sources of energy wastage. It consists of activities that seek to identify conservation opportunities before conducting or developing any energy-saving program. These audit programs are helpful in understanding and analysing the energy utilisation of any organisation. The audit programmes help to identify and reduce energy wastage.

The first and most important role of energy auditing is to identify the areas of energy consumption and to find the overuse for assessing the opportunity of saving energy. In this way, money can be saved, for example, during the audit of a factory; the employees of the factory can be trained for the use of energy-saving equipment. Also,o they would be made aware of the need for energy conservation. So there is an attitudinal change for reducing energy use and energy wastage.

6. Mention the advantages and limitations of using solar energy.

Ans: 

• Advantages
  • Environment friendly
  • Ample or unlimited availability.
• Limitations of solar energy
  • Limited capacity for the storage of sunlight.
  • Cloud cover may mask its usefulness.
  • Collecting equipment is expensive.

7. Write a short note on the importance of energy in your daily life.

Ans: 

• In an average home, for almost all types of activities like lighting, cooling and heating the house, for cooking, for running televisions, computers and other electrical gadgets, energy is used.
• Traffic lights are powered by electricity.
• In the transport sector, buses, trucks, trains, aeroplanes, ships, and automobiles are powered by coal, gasoline, diesel and gas. These are fossil fuels, and their overexploitation is causing scarcity.
• In the agricultural sectors, pumps for irrigation run on diesel (a fossil fuel) or electricity. Tractors, threshers, and combined harvesters are all fuel-intensive.
• In the industrial sectors, energy is required in huge amounts at various stages in the manufacturing of goods.

8. Justify the statement that ‘energy is the most important input for economic growth and human development.

Ans: Energy development is an integral part of economic development. 

• Economically developed countries use more energy per unit of economic output and have much more per capita energy consumption as compared to developing countries. 
• Energy has been universally recognised as one of the most important inputs for economic growth and human development. 
• Growth of the economy will stand global competitiveness only when it depends on cost-effective or cheaper, and environmentally friendly energy sources.
• Energy intensity is an indicator to show how efficiently energy is used in the economy.

9. How can we conserve energy at the community level for housing complexes

Ans: Energy conservation is a very sensitive issue throughout the world. In a society where money and especially financially advantageous options are available to us, we should follow the following measures to reduce energy consumption 

• All unnecessary lights should be turned off, especially when they are not in use.
• Energy use should be minimised during peak demand hours.
• Set computers, monitors, photocopiers and other business equipment to the energy-saving mode. Turn them off during long idle hours, such as lunch breaks.
• Skylights should be used for warehouses.
• Ensure that offices having conditioning have proper windows and all doors are closed when the air conditioner is in use.

Additional Study Materials

• Chapter 27B Importance of Energy in Society
• Chapter 28B Non-Renewable Sources of Energy
• Chapter 29B Renewable Sources of Energy – I
• Chapter 30B Renewable Sources of Energy – II