Global Environment.com

The importance of improving energy efficiency

What is energy efficiency?

Energy efficiency is the percentage of total energy input that does useful work (is not converted to low quality, essentially useless heat) in an energy conversion system. The easiest, fastest, and cheapest way to get more energy with the least environmental impact is to eliminate much of this energy waste by making lifestyle changes that reduce energy consumption: walking or biking for short trips, using mass transit, putting on a sweater instead of turning up the thermostat, and turning off unneeded lights.

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Why Is Reducing Energy Waste So Important?

Reducing energy waste is one of the planet's best and most important economic and environmental bargains. It

Makes no-renewable fossil fuels last longer.
Gives us more time to phase in renewable energy.
Decreases dependence on oil imports.
Lessen the need for military intervention in the oil-rich but politically unstable Middle East.
Reduces local and global environmental damage because less of each energy resource would provide the same amount of useful energy.
Is the cheapest and quickest way to slow projected global warming
Saves more money, provides more jobs, improves productivity, and promotes more economic growth per unit of energy than other alternatives.
Improves competitiveness in the international marketplace.

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Ways To Improve Energy Efficiency

How can we use waste heat?
How can we save energy in industry?
How can we save energy in producing electricity?
How can we save energy in transportation?
How can we save energy in buildings?

How can we use waste heat?

Could we save energy by recycling energy? No. The second law of energy tells us that we cannot recycle energy. However, we can slow the rate at which waste heat flows into the environment when high-quality energy is degraded. For a house, the best way to do this is to insulate it thoroughly, eliminate air leaks, and equip it with an air-to-air heat exchanger to prevent buildup of indoor air pollutants.

In office buildings and stores, waste heat from lights, computers, and other machines can be collected and distributed to reduce heating bills during cold weather; during hot weather, this heat can be collected and vented outdoors to reduce cooling bills. Waste heat from industrial plants and electrical power plants can be used to produce electricity (cogeneration); it can also be distributed through installed pipes to heat nearby buildings, greenhouses, and fish ponds, as is done in some parts of Europe.

How can we save energy in industry?

There are a number of ways to save energy and money in industry. One is cogeneration, the production of two useful forms of energy (such as steam and electricity) from the same fuel source. Waste heat from coal-fired and other industrial boilers can produce steam that spins turbines and generates electricity at roughly half the cost of buying it from a utility company. By using the electricity or selling it to a local power company for general use, a plant can save energy and money.

Replacing energy-wasting electric motors is another strategy. It would be cost-effective to scrap virtually all such motors and replace them with adjustable-speed drives.

energy can also be saved by switching to high-efficiency lighting. Additionally, computer-controlled energy management systems can turn off lighting and equipment in non production areas and make adjustments during periods of low production. recycling and reuse and making products that last longer and that are easy to repair and recycle also saves energy compared with using virgin resources.

How can we save energy in producing electricity?

Traditionally, utilities make more money by increasing the demand for electricity. This process encourages the building of often unnecessary power plants to send electricity to inefficient appliances, heating and cooling systems, and industrial plants. To make more money, many utilities encourage their customers to use (and thus waste) even more electricity - a classic example of harmful positive feedback in action.

A small but growing number of utility companies are trying to reverse this wasteful process by reducing the demand for electricity. By helping customers use electricity more efficiently, these companies do not need to finance and build expensive new power plants.

This new approach is known as demand-side management or the negawatt revolution. The reduce demand, utilities give customers cash rebates for buying efficient lights and appliances, free home-energy audits, low-interest loans for home weatherisation or industrial retrofits, and lower rates to households or industries meeting certain energy-efficiency standards. To make demand-side management feasible, utility regulators must allow utility investors to make a reasonable return on their money, based on the amount of energy the utilities save. Such a policy allows utility companies to shift their emphasis from producing megawatts to energy-saving negawatts.

How can we save energy in transportation?

The most important way to save energy (especially oil) and money in transportation is to increase the fuel efficiency of motor vehicles. Existing technology could raise current fuel efficiency to 35 miles per gallon by 2010. Doing this would cause a sharp drop in emissions of CO2 and other air pollutants, cut oil imports in half and create new jobs.

Since 1985 at least 10 automobile companies have made nimble and peppy prototype cars that meet or exceed current safety and pollution standards., with fuel efficiencies of 67-138 miles per gallon. If such cars were mass produced, their slightly higher costs would be more than offset by their fuel savings. The problem is that there is little consumer interest in fuel-efficient cars when the inflation-adjusted price of gasoline today is the lowest it has been since 1920. This under pricing of gasoline encourages energy waste and pollution by failing to include in its market price the many harmful social and environmental costs of gasoline, which consumers ultimately end up paying anyway.

To encourage consumers to buy energy-efficient vehicles, a system of revenue-neutral rebates and "freebates" be established for motor vehicles. Buyers of a new vehicle would pay a fee or receive a rebate depending on its fuel efficiency. the fees on inefficient vehicles would be used to pay for the rebates on efficient ones.

Conventional battery-powered electric cars might help reduce dependence on oil, especially for urban commuting and short trips. Electric vehicles are extremely quiet, need little maintenance, and can accelerate rapidly. The cars themselves, called zero-emissions vehicles, produce no air pollution. However, using coal and nuclear power plants to produce the electricity needed to recharge their batteries daily does produce air pollution and nuclear wastes - something called elsewhere pollution.

Greatly increased manufacture, disposal, and recycling of lead batteries for widespread use of electric vehicles could also greatly increase the input of toxic lead into the environment. If solar cells or wind turbines could be used for recharging the car's batteries, CO2 and other air pollution emissions would be virtually eliminated.

On the negative side, today's electric cars are not very efficient; they are equivalent to gasoline powered cars that get about 16-25 miles per gallon. current electric cars can travel only 50-100 miles. Their batteries must be recharged for 3-8 hours and must be replace every 30,000 miles. This requirement, plus the electricity costs for daily recharging and buying a charger, means that today's electric cars have twice the operating cost of gasoline powered cars.

Another way to save energy is to shift to more energy-efficient ways to move people and freight. More freight would be shifted from trucks and planes to more energy-efficient trains and ships. The fuel efficiency of other means of transport can also be increased. With improved aerodynamic design, turbo charged diesel engines, and radial tires, new transport trucks can be 50% more fuel efficient than today's conventional trucks.

How can we save energy in buildings?

Heating, cooling, and lighting buildings consume about one-third of the energy used by modern societies, which much of this energy unnecessarily wasted.

There are a number of ways to improve the energy efficiency of buildings. One is to build super-insulted houses. Although such houses typically cost 55 more to build than conventional houses of the same size, this extra cost is paid back by energy savings within 5 years and can save a homeowner £30,000-80,000 over a 40 year period.

Another way to save energy is to use the most energy-efficient ways to heat houses. The most energy-efficient ways to heat space are to build a super insulated house, use passive solar heating, and use high-efficiency (85-98% efficient) natural gas furnaces. The most wasteful and expensive way is to use electric resistance heating with the electricity produced by a coal-fired or nuclear power plant.

Heat pumps can save energy and money for space heating in warm climates, bit not in cold climates; at low temperatures they automatically switch to wasteful, costly electric resistance heating. Some heat pumps in their air conditioning mode are also much less efficient than many individual air conditioning units. Most heat pumps also require expensive repair every few years. However, manufacturers have developed some improved models that produce warmer air and more efficient than older models.

The energy efficiency of existing houses can be improved significantly by adding insulation, plugging leaks, and installing energy-saving windows.

We can also use the most energy-efficient ways to heat household water. An efficient method is to use tank less instant water heaters fired by natural gas or liquefied petroleum gas (LPG). These devices, widely used in many parts of Europe, heat the water instantly as it flows through a small burner chamber and provide hot water only when it is needed. A well-insulated, conventional natural gas or LPG water heater is also fairly efficient.

The most inefficient and expensive way to heat water for washing and bathing is to use electricity produced by any type of power plant.

Setting higher energy-efficient standards for new buildings would also save energy.

Another way to save energy is to buy the most energy-efficient appliances and lights.

Improvements in energy efficiency could be encouraged by giving rebates or tax credits for building-energy efficient buildings, for improving the energy efficiency of existing buildings, and for buying high-efficiency appliances and equipment.