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Summary
Chapter 21 covers energy conservation, management, and planning. Energy is essential for modern life, but we are running out of resources. Therefore, it is important to conserve energy by using it efficiently. Energy conservation involves using less energy without compromising productivity and comfort. Some key ways to achieve this include upgrading technology, improving operation and maintenance, and providing incentives for energy-saving practices.
In households, energy can be saved through simple habits, like using pressure cookers for cooking, turning off stoves before cooking is done, using public transport, and replacing bulbs with energy-efficient CFLs or LEDs. Industry, being the largest energy consumer in India, can contribute significantly by adopting efficient processes and energy-saving equipment. Similarly, the agricultural sector can save energy by using more efficient irrigation pumps.
The transport sector, another major consumer of energy, can benefit from promoting bicycles and improving public transport systems. Energy-efficient vehicles, better road conditions, and proper vehicle maintenance can further reduce energy use and pollution.
In the power sector, the concept of demand-side management is gaining importance. This approach encourages power companies to help reduce customer demand for energy, rather than just focusing on increasing supply. Rational pricing of energy also encourages careful use.
Alternative fuels like ethanol, methanol, hydrogen, and fuel cells offer potential solutions to reduce dependence on conventional fuels. These alternatives are environmentally friendly and efficient, but further development is needed for widespread use. Lastly, nanotechnology holds promise for improving the efficiency of energy devices and utilisation, making significant contributions to global energy savings and reducing emissions.
Textbook solutions
Multiple-Choice Questions
1. Which of the following is not a way to save electricity?
A. Use of CFLs & LEDs
B. Using batteries rather than mains
C. Minimising use of natural light
D. Defrosting the refrigerator regularly
Answer: B. Using batteries rather than mains
2. In India, which sector is the largest consumer of energy?
A. Industry
B. Agriculture
C. Transport
D. Power
Answer: A. Industry
3. Which part of agriculture consumes the maximum amount of energy?
A. Sowing of seeds
B. Tractor
C. Harvesting
D. Irrigation using water pumps
Answer: D. Irrigation using water pumps
4. Conservation of energy means
A. Using energy unrestricted
B. Not using energy at all
C. Using energy judiciously
D. All of these
Answer: C. Using energy judiciously
5. Device used in New Zealand to reduce hot water costs by two-thirds in a shed is
A. Octane rating
B. Electrolyte
C. Mahana Blue
D. Fuel cells
Answer: C. Mahana Blue
Short Answer Questions
1. What do you mean by conservation of energy?
Answer: Conservation of energy refers to the judicious use of energy resources. It involves avoiding wastage of energy and adopting methods to conserve energy without affecting productivity and comforts.
2. What is cogeneration?
Answer: Cogeneration means production of two useful forms of energy such as high temperature heat or steam and electricity from the same fuel source.
3. What is demand side management?
Answer: Demand side management strategies aim to influence or reduce the demand for a product or service by pricing, incentives, and other policies.
4. What is an energy audit?
Answer: Energy audit is an official scientific study of energy consumption at any level (regional, organisational or plant level) with the aim of reduction in energy costs and consumption without affecting the productivity and comforts, and suggesting methods for energy conservation and reduction in energy costs.
5. What is energy planning?
Answer: Energy planning is a process in which data regarding demand, shortfall, production, imports, etc., are collected for the past years, the trends are analysed, and based on this, the demand for future is predicted. It is part of the energy strategy to ensure uninterrupted energy supply to consumers on both short-term and long-term bases.
6. What is a fuel cell?
Answer: Fuel cells are power-generating devices that electrochemically convert the chemical energy of a fuel to electricity. As there is no combustion involved, the efficiency of fuel cells is very high.
7. What is nanotechnology?
Answer: Nanotechnology is a technology that involves the study and manipulation of matter on a nanometre (1–100 billionth of a metre) scale.
8. Why is water-free alcohol required?
Answer: Water-free alcohol is required because water and alcohol combined cannot dissolve in gasoline, and all traces of water must be removed for fuel ethanol to work as an effective alternative among fuel sources.
9. Why is hydrogen considered unsafe as an ordinary fuel?
Answer: Hydrogen is considered unsafe as an ordinary fuel due to its explosive nature.
Long Answer Questions
1. How can we promote energy conservation?
Answer: The ways in which we can promote energy conservation are as below:
- Using, producing, managing and distributing energy more efficiently.
- Improving efficiency by technological upgradation and improved operation and maintenance.
- Providing incentives for energy-saving equipment, practices and techniques.
- Pricing energy in a realistic way.
2. What are the steps you can take in your household to save energy?
Answer: We can save energy by adopting the following steps:
- We should reduce wasteful consumption by not buying unnecessary things.
- We can also save energy by using energy-efficient equipment. It requires investment in either new equipment or in proper maintenance of older equipment.
- Energy-efficient models may cost more initially than the conventional models, but they save money in the long run.
- Energy conservation is the cheapest and the largest source of energy available to us.
3. What changes in transport system can help to save energy?
Answer: The changes in the transport system that can help save energy are:
- Use public transport whenever possible.
- Walk or cycle for short distances.
- Get your vehicle serviced regularly to keep it in good condition and to keep petrol consumption down.
- Using improved aerodynamics to minimise drag can increase vehicle fuel efficiency.
- Reducing vehicle weight can also improve fuel economy. This is why composite materials are widely used in car bodies.
- More advanced tyres, with decreased road friction and rolling resistance, can save fuel.
- Fuel economy can be improved by up to 3.3% by keeping tyres inflated to the correct pressure.
4. What are the benefits of energy conservation?
Answer: The benefits of energy conservation are as follows:
- Saves money and helps in saving fossil fuels.
- Reduces dependence on imported energy resources.
- It is the least-cost option for increasing energy supply.
5. Explain the construction of a fuel cell with the help of a diagram.
Answer: Fuel cells are power-generating devices that electrochemically convert the chemical energy of a fuel to electricity. As there is no combustion involved, as in the case of heat engines, the efficiency of fuel cells is very high. The basic construction of a fuel cell consists of two electrodes, which are separated by an electrolyte. Hydrogen is fed to the anode while oxygen is fed to the cathode. They ultimately react and form electricity and water.
H₂ anode → Hydrogen H₂ electrolyte → O₂ cathode (Air)
Overall reaction: H₂ + ½O₂ → H₂O + electricity
6. What are the advantages of a fuel cell?
Answer: The advantages of a fuel cell are as follows:
- They have low emissions as compared to conventional vehicles.
- Fuel cells are modular and can be given different shapes to fit available space.
- In fuel-cell vehicles, since chemical energy is directly converted to electricity, no energy is lost to heat.
- It is two to three times more efficient than an internal combustion engine in converting fuel to power.
7. What are the advantages of ethanol as a fuel?
Answer: The advantages of ethanol as a fuel are:
- It reduces air pollution.
- It reduces dependence on imported fuels.
- It is applicable for both light and heavy vehicles.
- Maintenance assistance required is more or less identical to that of conventional fuels.
8. Write the ways to enhance a vehicle’s energy efficiency.
Answer: The ways to enhance a vehicle’s energy efficiency are:
- Using improved aerodynamics to minimise drag.
- Reducing vehicle weight by using composite materials in car bodies.
- Using more advanced tyres with decreased road friction and rolling resistance.
- Keeping tyres inflated to the correct pressure to improve fuel economy by up to 3.3%.
- Improving vehicle maintenance to ensure fuel efficiency.
- Installing fuel-injected, computer-controlled engines to reduce energy wastage.
- Using energy-efficient vehicles like bicycles.
9. Explain the energy efficiency in: (i) production, (ii) transportation, (iii) utilisation.
Answer: (i) In Production: Energy efficiency means not only efficiency in the consumption of energy but also efficiency in its generation and distribution. In thermal power plants and factories, cogeneration can be used. Cogeneration means the production of two useful forms of energy from the same source.
(ii) In Transportation: The technical experts of energy sources work on how to minimise the transport or transmission losses. Some of the points considered are:
- Location of the energy-generating plant.
- Network configuration of the generating plant.
- The types of transformers and their capacity.
- Length of the electric lines. A lesser length would lessen the loss.
- The material design and type of cable.
- The current in the line. More current would double the loss.
(iii) In Utilisation: The growing population and urbanisation have created huge demand for energy in India. Energy efficiency is the goal to reduce the amount of energy we use in our daily life. Some of these ways are:
- Installing LED lights.
- Reducing the use of heaters or coolers by insulating the home.
- Using energy-efficient vehicles like bicycles.
- Turning off lights in unoccupied rooms.
- Switching off the TV at night.
- Installing low-consuming electrical equipment at home.
Think and Answer
1. Prerna thinks it below her dignity to travel in public transport. She goes to her office in a car though there is an efficient public transport system in her area. What would you suggest to her?
Answer: I would suggest that Prerna reconsider her view on using public transport. Public transport is an excellent way to conserve energy and reduce environmental pollution. By using a car, she contributes to air pollution, traffic congestion, and unnecessary fuel consumption. Public transport is more energy-efficient, cost-effective, and helps in reducing the overall carbon footprint. It also lessens the burden on non-renewable energy sources like petrol and diesel. Moreover, using public transport reflects social responsibility and environmental awareness, values that transcend personal status or dignity.
2. Sachin is quite rich. He thinks conservation of energy should be practised by poor people only. What do you think?
Answer: Sachin’s view is incorrect. Conservation of energy is a global responsibility that should be practised by everyone, regardless of their financial status. The rich, who generally consume more energy through their lifestyles, should be more mindful of conserving it. Energy conservation helps in reducing the pressure on finite resources like fossil fuels, decreases pollution, and helps to combat climate change. Practising energy conservation is about ensuring a sustainable future for everyone, and the rich, by setting an example, can play a significant role in promoting sustainable practices. Everyone, rich or poor, benefits from a healthier, more sustainable environment.
Extras MCQs
1. What is the largest consumer of electricity in India?
A. Industry
B. Agriculture
C. Transport
D. Residential sector
Answer: A. Industry
14. What method is suggested to improve the efficiency of energy utilization in homes?
A. Use of incandescent bulbs
B. Installation of LED lights
C. Keeping heaters on all day
D. Increasing the use of coolers
Answer: B. Installation of LED lights
Extra Questions and Answers
1. What is energy conservation?
Answer: Energy conservation refers to the judicious use of energy resources. It involves avoiding wastage of energy and adopting methods to conserve energy without affecting productivity and comfort. It means using less energy, more wisely than before.
41. How can energy be saved in electric irrigation pumps in India?
Answer: Replacing high-friction components like foot valves with low-friction ones in India’s electric irrigation pumps could save 35% of the electricity they use, which would save more than 2000 MW of power.
Ron’e Dutta is a journalist, teacher, aspiring novelist, and blogger. He manages Online Free Notes and reads Victorian literature. His favourite book is Wuthering Heights by Emily Bronte and he hopes to travel the world. Get in touch with him by sending him a friend request.
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