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Here is a compilation of essays on ‘Energy Efficiency’ for class 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Energy Efficiency’ especially written for school and college students.
Essay on Energy Efficiency
Essay Contents:
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- Essay on the Meaning of Energy Efficiency
- Essay on the Concept of Energy Efficiency
- Essay on the Strategies for Energy Efficiency
- Essay on the Elements of Energy Efficiency
Essay # 1. Meaning of Energy Efficiency:
Energy efficiency may refer to:
i. Efficient energy use.
ii. Energy conversion efficiency, the ratio between the output and input of an energy conversion machine.
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iii. Energy conservation, efforts made to reduce energy consumption.
Efficient energy use, sometimes simply called energy efficiency, is using less energy to provide the same level of energy service. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature. Another example would be installing fluorescent lights and or skylights instead of incandescent lights to attain the same level of illumination.
Compact fluorescent lights use two-thirds less energy and may last 6 to 10 times longer than incandescent light bulbs. Efficient energy use is achieved primarily by means of a more efficient technology or processes rather than by changes in individual behaviour.
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Energy efficient buildings, industrial processes and transportation could reduce the world’s energy needs in 2050 by one third and help controlling global emissions of greenhouse gases, according to the International Energy Agency.
Energy efficiency and renewable energy are said to be the twin pillars of sustainable energy policy.
Making homes, vehicles and businesses more energy efficient is seen as a largely untapped solution to addressing the problems of pollution, global warming, energy security and fossil fuel depletion. Many of these ideas have been discussed for years, since the 1973 oil crisis brought energy issues to the forefront.
Energy efficiency has proved to be a cost-effective strategy for building economics without necessarily growing energy consumption.
Energy Conversion Efficiency:
Energy conversion efficiency is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The useful output may be electric power, mechanical work or heat. Output energy is always lower than input energy.
Energy conversion efficiency is not defined uniquely, but instead depends on the usefulness of the output. All or part of the heat produced from burning a fuel may become rejected waste heat if, for example, work is the desired output from a thermodynamic cycle.
Even though the definition includes the notion of usefulness, efficiency is considered a technical or physical term. Goal or mission oriented terms include effectiveness and efficacy.
Generally, energy conversion efficiency is a dimensionless number between 0 and 1.0 or 0 to 100%. Efficiencies may not exceed 100%, e.g., for a perpetual motion machine. However, other effectiveness measures that can exceed 1.0 are used for heat pumps and other devices that move heat rather than convert it.
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One of the purpose of the energy audit is to check the energy conversion efficiency of equipment in the system.
Essay # 2. Concept of Energy Efficiency:
The concept of energy efficiency has gained substantial importance in the recent times. The supply constraint of fossil fuels makes the strategies for energy efficiency all the more important.
Conservation of energy is the main prerequisite for energy efficiency. Use of alternative or renewable sources of energy is also crucial in the context of energy efficiency. There are several measures that support the initiatives of improved energy efficiency. Use of energy-saving industrial appliances is quite helpful for conservation of energy.
A number of energy efficient equipment and systems such as high- efficiency motors, energy efficient lighting, etc. have come up in the recent times. All these devices are designed in such a way that the requirement of energy would be quite low while running them. The added advantage with the energy-saving appliances is that they are environment friendly and thereby help in keeping the pollution level low.
Over the years, different policies have been implemented to promote the ideas of energy efficiency. Among the major energy efficiency policies enhanced building code, industrial energy efficiency measures, federal appliance and equipment efficiency standards and tax incentives are worth mentioning.
In addition to these, use of bio fuels, biodiesel, biogas and geothermal energy for cooking and transportation purposes come in handy to support the policies of energy efficiency. A general awareness needs to be developed among the common mass to cut down dependence on fossil fuels and ensure efficient use of energy.
Essay # 3. Strategies for Energy Efficiency:
Energy efficiency programs are designed to make the environment clean and green. Energy efficiency strategies including popularizing the use of renewable sources of energy are designed to reduce the damage that fossil fuel dependence is causing to the environment.
Use of alternative sources of energy like biogas, bio fuels, solar power and the like reduce the emission of harmful greenhouse gases. This is turn helps in reducing the amount of pollutants in the atmosphere, thereby reducing the likelihood of unfavourable climatic changes caused by global warming.
In recent times there has been considerable improvement in awareness levels among consumers regarding the different aspects of energy efficiency and renewable energy. Organizations that work for protection of environment have initiated a number of energy efficiency programs all over the world.
Industries, households, schools, Government and businesses account for over 70% of the total energy consumed in a nation. The success of any energy efficiency program crucially depends on how well it ensures energy efficiency in the above-mentioned entities.
To keep the energy prices within a reasonable limit and assure energy security are the other challenges faced by the energy efficiency programs. These programs also put stress on cost effective use of energy.
To design strategies for long-term energy conservation constitutes an important part of all the energy efficiency programs. The organizers of these programs keep themselves updated about the latest developments in the field of energy efficiency.
Use of new technologies makes the energy efficiency programs well equipped to address the various issues related to the efficient use of energy. Energy efficiency programs need to set specific time frame for achievement and evaluation of the goals. Consumer’s participation is very crucial for any energy efficiency program to be successful in the long-run.
Due to the increasing concern over environmental degradation and adverse climatic change, the energy efficiency programs have gained considerable importance over the passage of time.
Essay # 4. Elements of Energy Efficiency:
Energy efficiency may refer to:
a. Efficient energy use.
b. Energy conversion efficiency, the ratio between the output and input of an energy conversion machine.
c. Energy conservation, efforts made to reduce energy consumption.
a. Efficient Energy Use:
Efficient energy use, sometimes simply called energy efficiency, is using less energy to provide the same level of energy service. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature.
Another example would be installing fluorescent lights and/or skylights instead of incandescent lights to attain the same level of illumination. Compact fluorescent lights use two-thirds less energy and may last 6 to 10 times longer than incandescent light bulbs. Efficient energy use is achieved primarily by means of a more efficient technology or processes rather than by changes in individual behavior.
Energy efficient buildings, industrial processes and transportation could reduce the world’s energy needs in 2050 by one third and help controlling global emissions of greenhouse gases, according to the international energy agency.
Energy efficiency and renewable energy are said to be the twin pillars of sustainable energy policy.
Making homes, vehicles and businesses more energy efficiency is seen as a largely untapped solution to addressing the problems of pollution, global warming, energy security and fossil fuel depletion. Many of these ideas have been discussed for years, since the 1973 oil crisis brought energy issues to the forefront.
Energy efficiency has proved to be a cost-effective strategy for building economies without necessarily growing energy consumption. There are abundant opportunities to save 70 to 90% of the energy and cost for lighting, fan and pump systems; 50% for electric motors and 60% in areas such as heating, cooling, office equipment and appliances.
Some of the examples of efficient energy use in some of the following fields is as follows:
(i) Appliances:
Modern energy-efficient appliances, such as refrigerators, freezers, ovens, stoves, dishwashers and clothes washers and dryers, use significantly less energy than older appliances. Current energy efficient refrigerators, for example, use 40 percent less energy than conventional models did in earlier.
Modern power management systems also reduce energy usage by idle appliances by turning them off or putting them into a low-energy mode after a certain time. Many countries identify energy-efficient appliances using an energy star label.
The impact of energy efficiency on peak demand depends on when the appliance is used. For example, an air conditioner uses more energy during the afternoon when it is hot. Therefore, an energy efficient air conditioner will have a larger impact on peak demand than off-peak demand. An energy efficient dishwasher, on the other hand, uses more energy during the late evening when people do their dishes. This appliance may have little to no impact on peak demand.
(ii) Building Design:
A building’s location and surroundings play a key role in regulating its temperature and illumination. For example, trees/landscaping and hills can provide shade and block wind. In cooler climates, designing buildings with a south facing windows increases the amount of sun (ultimately heat energy) entering the building, minimizing energy use, by maximizing passive solar heating.
Tight building design, including energy-efficient windows, well-sealed doors and additional thermal insulation of walls, basement slabs and foundations can reduce heat loss by 25 to 50 percent.
Dark roofs may become up to 39°C (70°F) hotter than the most reflective white surfaces and they transmit some of this additional heat inside the building. US studies have shown that lightly colored roofs use 40 percent less energy for cooling than buildings with darker roofs.
White roof systems save more energy in sunnier climates. Advanced electronic heating and cooling systems can moderate energy consumption and improve the comfort of people in the building.
Proper placement of windows and skylights and use of architectural features that reflect light into a building, can reduce the need for artificial lighting. Increased use of natural and task lighting have been shown by one study to increase productivity in schools and offices. Compact fluorescent lights use two-thirds less energy and may last 6 to 10 times longer than incandescent light bulbs. Newer fluorescent lights produce a natural light and in most applications they are cost effective, despite their higher initial cost, with payback periods as low as a few months.
Effective energy-efficient building design can include the use of low cost passive infra reds (PIRs) to switch-off lighting when areas are un-occupied such as toilets, corridors or even office areas out-of-hours. In addition, lux levels can be monitored using daylight sensors linked to the building’s lighting scheme to switch on/off or dim the lighting to pre-defined levels to take into account the natural light and thus reduce consumption. Building management systems (BMS) link all of this together in one centralized computer to control the whole building’s lighting and power requirements.
The choice of which space heating or cooling technology to use in buildings can have a significant impact on energy use and efficiency. For example, replacing an older 50% efficient natural gas furnace with a new 95% one will dramatically reduce energy use, carbon emissions and winter natural gas bills. Ground source heat pumps can be even more energy efficiency and cost effective.
These systems use pumps and compressors to move refrigerant fluid around a thermodynamic cycle in order to “pump” heat against its natural flow from hot to cold, for the purpose of transferring heat into a building from the large thermal reservoir contained within the nearby ground. The end result is that heat pumps typically use four times less electrical energy to deliver an equivalent amount of heat than a direct electrical heater does.
Another advantage of a ground source heat pump is that it can be reversed in summertime and operate to cool the air by transferring heat from the building to the ground. The disadvantage of ground source heat pumps is their high initial capital cost, but this is typically recouped within 5 to 10 years as a result of lower energy use.
Smart meters are slowly being adopted by the commercial sector to highlight to staff and for internal monitoring purposes the building’s energy usage in a dynamic presentable format. The use of power quality analysers can be introduced into an existing building to assess usage, harmonic distortion, peaks, swells and interruptions amongst others to ultimately make the building more energy- efficient. Often such meters communicate by using wireless sensor networks.
(iii) Industry:
In industry, when electricity is generated, the heat which is produced as a by-product can be captured and used for process steam, heating or other industrial purposes. Conventional electricity generation is about 30 percent efficient, whereas combined heat and power (also called co-generation) converts up to 90 percent of the fuel into usable energy.
Advanced boilers and furnaces can operate at higher temperatures while burning less fuel. These technologies are more efficient and produce fewer pollutants.
Over 45 percent of the fuel used by US manufacturers is burnt to make steam. The typical industrial facility can reduce this energy usage 20 percent (according to the US department of energy) by insulating steam and condensate return lines, stopping steam leakage and maintaining steam traps.
Electric motors usually run on a constant flow of energy, but an adjustable speed drive can vary the motor’s energy output to match the load. This achieves energy savings ranging from 3 to 60 percent, depending on how the motor is used. Motor coils made of superconducting materials can also reduce energy losses. Motors may also benefit from voltage optimization.
Many industries use compressed air for sand blasting, painting or other tools. According to the US department of energy, optimizing compressed air systems by installing variable speed drives, along with preventive maintenance to detect and fix air leaks, can improve energy efficiency 20 to 50 percent.
(iv) Vehicles:
The estimated energy efficiency for an automobile is 280 Passenger-mile/106 Btu. There are several ways to enhance a vehicle’s energy efficiency. Using improved aerodynamics to minimize drag can increase vehicle fuel efficiency. Reducing vehicle weight can also improve fuel economy, which is why composite materials are widely used in car bodies.
More advanced tires, with decreased tire to road friction and rolling resistance, can save gasoline. Fuel economy can be improved by up to 3.3% by keeping tires inflated to the correct pressure. Replacing a clogged air filter can improve a cars fuel consumption by as much as 10 percent on older vehicles. On newer vehicles (1980’s and up) with fuel-injected, computer- controlled engines, a clogged air filter has no effect on mpg but replacing it may improve acceleration by 6-11 percent.
Energy-efficient vehicles may reach twice the fuel efficiency of the average automobile. Cutting-edge designs, such as the diesel Mercedes-Benz Bionic concept vehicle have achieved a fuel efficiency as high as 84 miles per US gallon (2.8 L/100 km; 101 mpg-imp), four times the current conventional automotive average.
The mainstream trend in automotive efficiency is the rise of electric vehicles (electric or hybrid electric). Hybrids, like the Toyota Prius, use regenerative braking to recapture energy that would dissipate in normal cars; the effect is especially pronounced in city driving, plug-in hybrids also have increased batter, capacity which makes it possible to drive for limited distances without burning any gasoline; in this case, energy efficiency is dictated by whatever process (coal-burning, hydroelectric renewable source etc.) created the power.
Plug-ins can typically drive for around 40 miles (64 km) purely on electricity without recharging; if the battery runs low, a gas engine kicks in allowing for extended range. Finally, all-electric cars are also growing in popularity; the Tesla Roadster sports can is the only high-performance all-electric car currently on the market and others are in preproduction.
b. Energy Conservation and Energy Efficiency:
Energy conservation is broader than energy efficiency in that it encompasses using less energy to achieve a lesser energy service, for example through behavioral change, as well as encompassing energy efficiency.
Examples of conservation without efficiency improvements would be heating a room less in winter, driving less or working in a less brightly lit room. As with other definitions, the boundary between efficiency energy use and energy conservation can be fuzzy, but both are important in environmental and economic terms. This is especially the case when actions are directed at the saving of fossil fuels.
Sustainable Energy:
Energy efficiency and renewable energy are said to be the ‘twin pillars’ of a sustainable energy policy. Both strategies must be developed concurrently in order to stabilize and reduce carbon dioxide emissions. Efficient energy use is essential to slowing the energy demand growth so that rising clean energy supplies can make deep cuts in fossil fuel use.
If energy use grows too rapidly, renewable energy development will chase a receding target. Likewise, unless clean energy supplies come online rapidly, slowing demand growth will only begin to reduce total carbon emissions; a reduction in the carbon content of energy sources is also needed. A sustainable energy economy thus requires major commitments to both efficiency and renewable.
Rebound Effect:
If the demand for energy services remains constant, improving energy efficiency will reduce energy consumption and carbon emissions. However, many efficiency improvements do not reduce energy consumption by the amount predicted by simple engineering models.
This is because they make energy services cheaper and so consumption of those services increases. For example, since fuel efficient vehicles make travel cheaper, consumers may choose to drive further and/or faster, thereby offsetting some of the potential energy savings. This is an example of the direct rebound effect.
Estimates of the size of the rebound effect range from roughly 5 to 40%. The rebound effect is likely to be less than 30% at the household level and may be closer to 10% for transport. A rebound effect of 30% implies that improvements in energy efficiency should achieve 70% of the reduction in energy consumption projected using engineering models.
Since more efficient (and hence cheaper) energy will also lead to faster economic growth, there are suspicions that improvements in energy efficiency may eventually lead to even faster resource use. This was postulated by economists in the 1980s and remains a controversial hypothesis. Ecological economists have suggested that any cost savings from efficiency gains be taxed away by the government in order to avoid this outcome.
Energy Conversion Efficiency:
Some specific terms related to energy efficiency are as follows:
i. Electrical efficiency, useful power output per electrical power consumed,
ii. Mechanical efficiency, where one form of mechanical energy (e.g. potential energy of water) is converted to mechanical energy (work),
iii. Thermal efficiency or fuel efficiency, useful heat and/or work output per input energy such as the fuel consumed,
iv. ‘Total efficiency’, e.g. for cogeneration, useful electric power and heat output per fuel energy consumed. Same as the thermal efficiency.
v. Luminous efficiency, what portion of the emitted electromagnetic radiation is usable for human vision.
Example of Energy Conversion Efficiency:
c. Energy Efficiency Potential in India:
The industrial sector consumes about half of the total commercial energy available in India, 70% of which is in energy-intensive sectors – fertilizers, aluminium, textiles, cement, iron and steel and paper -15-25% of this is avoidable.
i. 5-10% energy saving is possible simply by better housekeeping measures.
ii. Another 10-15% is possible with small investment like low cost retrofits, use of energy efficient devices and controls, etc.
The quantum of saving is much higher if high cost measures are included (major retrofit, process modifications etc.)
Industry and transport sectors have the highest potential for energy savings.