ENERGY EFFICIENCY

Posted on

energy-efficiency

ENERGY EFFICIENCY

Why be energy efficient?   Are we really saving that much?   What is the importance of being energy efficient and saving energy?  Does energy efficiency tie in with anything else?  Are energy efficiency and energy conservation the same thing?

I hope this is helpful in putting things into perspective.   There is good information out there, which could be included in my book.  Energy efficiency is one of the easiest and most cost effective ways to combat climate change, clean the air we breathe, improve the competitiveness of our businesses and reduce energy costs for consumers.    Energy efficiency is “using less energy to provide the same service”.

When you replace a single pane window in your house with an energy-efficient one, the new window prevents heat from escaping in the winter, so you save energy by using your furnace or electric heater less while staying comfortable. In the summer, efficient windows keep the heat out, so the air conditioner does not run as often, hence saving electricity.  At the same time, when you replace an appliance, such as a refrigerator, washing machine, office equipment, a computer or printer, with a more energy-efficient model, the new equipment provides the same service, but uses less energy. This saves you money on your energy bill, and reduces the amount of greenhouse gases going into the atmosphere.

Energy efficiency is not energy conservation; energy conservation is reducing or going without a service to save energy.  But both efficiency and conservation help reduce greenhouse gas emissions.        An example is: Turning off a light is energy conservation. Replacing an incandescent lamp with a compact fluorescent lamp (which uses much less energy to produce the same amount of light) is energy efficiency.

Efficient energy use is the goal to reduce the amount of energy required to provide products and services. Insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature.  Also, by installing fluorescent lights or natural skylights greatly reduces the amount of energy required to attain the same level of illumination compared with using traditional incandescent light bulbs.  Compact fluorescent lights use one-third the energy of incandescent lights and may last 6 to 10 times longer. Improvements in energy efficiency are generally achieved by adopting a more efficient technology or production processes or by application of commonly accepted methods to reduce energy losses.  There are many motivations to improve energy efficiency. Reducing energy use reduces energy costs and may result in a financial cost saving to consumers if the energy savings offset any additional costs of implementing an energy efficient technology. Reducing energy use is also seen as a solution to the problem of reducing carbon dioxide emissions.   Energy efficiency and renewable energy are said to be the twin pillars of sustainable energy policy and are high priorities in the sustainable energy hierarchy.  In many countries energy efficiency is also seen to have a national security benefit because it can be used to reduce the level of energy imports from foreign countries and may slow down the rate at which domestic energy resources are depleted.

Energy efficiency has proved to be a cost-effective strategy for building economies without necessarily increasing energy consumption.   A recent study  points out that in industrial settings, “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.   Up to 75% of the electricity used in the U.S. today could be saved with efficiency measures that cost less than the electricity itself. The same holds true for home-owners, leaky ducts have remained an invisible energy culprit for years.

Modern appliances, such as, freezers, ovens, Stoves, dishwashers, washing machines dryers, use significantly less energy than older appliances. Installing a clothesline will significantly reduce your energy consumption as your dryer will be used less. The replacement of old appliances is one of the most efficient global measures to reduce emissions of greenhouse gases. 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 energy input labeling.   The impact of energy efficiency on peak demand depends on when the appliance is used. 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.

The location of a building and its 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 northern hemisphere buildings with south facing windows and southern hemisphere buildings with north 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.    Proper placement of windows and skylights as well as the use of architectural features that reflect light into a building can reduce the need for artificial lighting. Increased use of natural and task lighting has 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.

The choice of which space heating or cooling technology to use in buildings can have a significant impact on energy use and efficiency. Replacing an older 50% efficient natural gas furnace with a new 95% efficient one will dramatically reduce energy use, carbon emissions, and winter natural gas bills. Ground source heat pumps can be even more energy efficient 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 five to ten years as a result of lower energy use.

Industry uses a large amount of energy to power a diverse range of manufacturing and resource extraction processes. Many industrial processes require large amounts of heat and mechanical power, most of which is delivered as natural gas, petroleum fuels and electricity.  In addition some industries generate fuel from waste products that can be used to provide additional energy.  Because industrial processes are so diverse it is impossible to describe the multitude of possible opportunities for energy efficiency in industry. Many depend on the specific technologies and processes in use at each industrial facility. There are, however, a number of processes and energy services that are widely used in many industries.

Various industries generate steam and electricity for subsequent use within their facilities. When electricity is generated, the heat that 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% efficient, whereas combined heat and power 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 by insulating steam and condensate return lines, stopping steam leakage, and maintaining steam traps.

Electric motors usually run at a constant speed, but a variable speed drive allows the motor’s energy output to match the required load. This achieves energy savings ranging from 3 to 60 percent, depending on how the motor is used. Motor coils made of superconductive materials can also reduce energy losses.

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 cars fuel consumption by as much as 10 percent on older vehicles. On newer vehicles 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 fuel efficiency as high as 84 miles per US gallon four times the current conventional automotive average.

The mainstream trend in automotive efficiency is the rise of electric vehicles (all electric or hybrid electric). Hybrids use regenerative breaking to recapture energy that would dissipate in normal cars; the effect is especially pronounced in city driving.  Plug in hybrids also have increased battery capacity, which makes it possible to drive for limited distances without burning any gasoline; in this case, energy efficiency is dictated by whatever process (such as coal-burning, hydroelectric, or renewable source) 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 car is the only high-performance all-electric car currently on the market, and others are in preproduction.

Alternative fuels, known as non-conventional or advanced fuels, are any materials or substances that can be used as fuels, other than conventional fuels. Some well-known alternative fuels include biodiesel, bio alcohol, (methane, ethanol, butanol), chemically stored electricity (batteries and fuel cells), hydrogen,  non-fossil methane, non-fossil  natural gas, vegetable oil, and other biomass sources.

Energy conservation is broader than energy efficiency in including active efforts to decrease energy consumption, for example through behavioral change, in addition to using energy more efficiently. Examples of conservation without efficiency improvements are heating a room less in winter, using the car less, air-drying your clothes instead of using the dryer, or enabling energy saving modes on a computer. The boundary between efficient energy use and energy conservation can be fuzzy, but both are important in environmental and economic terms. This is the case when actions are directed at the saving of fossil fuels.  Energy conservation is a challenge requiring policy programmes, technological development and behavioral change to go hand in hand. Many energy intermediary organizations, for example governmental or non-governmental organizations on local, regional, or national level, are working on often publicly funded programmes or projects to meet this challenge.

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 renewables.

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 farther, thereby offsetting some of the potential energy savings. Similarly, an extensive historical analysis of technological efficiency improvements has conclusively shown that energy efficiency improvements were almost always outpaced by economic growth, resulting in a net increase in resource use and associated pollution.

Reducing GHGs substantially—enough to slow down climate change—will require many different approaches, including both energy efficiency and renewable energy, carbon-neutral transportation fuels, and possibly storing GHG emissions safely away from the atmosphere.

Kathy Kiefer

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s