> home
> About
> Contact Us
> Editorial Info
> IEEE-USA

10.08

Energy Conservation:
Past & Future

By Patrick E. Meyer and George F. McClure

The history of initiatives to conserve energy use is as long as the use of energy itself. Humans have always attempted to do more with less — it is in our nature to do so. But it was not until the 1970s that the desire to conserve became great enough to infiltrate federal-level policy. The energy crisis that erupted in 1973 was the major turning point for federal-level policy.

Today, it is hard to imagine a time when oil cost $7 to $8 per barrel, as it did in 1971. Oil was so cheap that there was no immediate need to conserve fuel, until the OPEC oil embargo of 1973 brought the issue to our attention. In 1974, the Ford Foundation released a two-year study, A Time to Choose: America's Energy Future Final Report [1], on the prospects for more efficient energy utilization. It showed that from 1950 to 1970, U. S. energy consumption grew at a rate of 3.5 percent per year. [2] Although energy consumption would continue to increase in the ensuing years, from the crisis onward, the nation would witness an impressive decoupling of growth in energy consumption and gross domestic product (GDP) (PEW, 2000). In other words, we started to do more with less. Most notably, the energy crises of the 1970s prompted a tremendous expansion of legislation for increased research and development of renewable energy technologies. [3] The Energy Tax Act of 1978 markedly promised residential energy income tax credits of up to $2,200 for solar and wind energy equipment expenditures. Further, it promised up to 25 percent tax credit of the cost of renewable energy technologies for businesses. [4]

Energy prices reached a high point in 1980 during the Iran hostage crisis, but then fell to early 1973 levels of about $38 per barrel. The result of the price drop was a slight downturn in energy conservation initiatives the 1980s. Despite the progressive actions taken in the 1970s towards conservation and the promotion of renewable energy, the 1980s proved to be a period in which many of the most constructive ideas from the 1970s wavered and collapsed. In the 1980s, no substantial federal-level legislation aimed at conservation, efficiency, or renewable energy was passed; although it can be argued that in the late-1980s work had already begun for the Energy Policy Act (EPACT) of 1992. By the early 1990s, interest in conservation and renewables returned. Two of the most significant pieces of legislation to follow were the EPACTs of 1992 and 2005.

EPACT 1992 set goals, created mandates, and amended utility laws to increase clean energy use, improve overall efficiency, and promote energy conservation. [5] Specifically, the Act established a permanent 10 percent business energy tax credit for investments in solar and geothermal equipment, as well as a 10-year production tax credit for privately and investor-owned wind projects and biomass plants. It would be another 13 years before legislation of the same magnitude would clear the halls of Congress. EPACT 2005 promoted residential efficiency, increased appliance and commercial product efficiency, reduced Federal government energy use, and sought to diversify the nation’s energy supply with renewable sources.

Yet, the legislation takes us only so far, and, in reality, affects less people than one would hope. In particular, residential energy consumers in particular were slow to experience the impact of the legislation contained in either of the EPACTs. Although the acts served to increase the availability and prominence of conservation and renewable alternatives, the last step is usually dependent on the end user. So, we must ask the question: what can residential home owners do to conserve energy?

The foremost method for a residential consumer to conserve energy is by incorporating passive design features into a home. Passive design features allow for a reduction in heating and cooling load, and an increase in natural lighting and heating. Many of these methods have proven to be very cost effective in a wide range of areas and various applications. Such measures include:

1. Solar water heaters. Passive solar water heaters move household water or a heat-transfer fluid through the system without pumps. The benefit is that they have no electric components to break, thus making them more reliable, easier to maintain, and possibly longer lasting than active systems . [6] Two types of passive solar water heaters include batch heaters, and thermosiphon systems. Batch heaters consist of one or more storage tanks placed in an insulated box, with a glazed side facing the sun. These systems can be mounted on the ground or the roof. Thermosiphon systems rely on natural convection to circulate water through collectors and to a tank. In these systems, warm water rises to an upper tank while cooler water flows down pipes, causing circulation. [7][8]
    

2. Convective loop/double shell design. Convective loop or double shell design involves building a space between the inner and outer walls of the home, allowing for convective circulation of air. In the winter, the sun heats the air in the space and circulates it to locations of the house needing warm air. In the summer, the system can be vented during the day, and can intake cool air at night. This system could include a non-insulated basement floor which would act as a heat source in the winter and heat sink in the summer. [9]
    

3. Efficient building components. Efficient components can greatly increase the overall energy efficiency of a home. Such components include efficient roof and wall insulation, dual-pane (or tri-pane) windows and dual-pane glass doors. [10] Further, air sealing is a vitally important component. Air leakage can occur when outside air enters a house through cracks and openings. Properly sealing such cracks and openings can greatly increase heating and cooling efficiency. [11]
    

4. Natural day lighting. The use of natural day lighting has become an increasingly popular option for improving residential energy efficiency. Properly insulated modern windows, and advances in lighting design allow for the efficient use of natural light to reduce the need for artificial lighting during the day. [12] South-facing windows are the most advantageous for day lighting, but north-facing windows also work well. East- and west-facing windows should be limited due to their tendency to cause glare, and to admit a lot of heat during the summer. [13]
    

5. Window glazing. Glazing is the process of applying a tinted, but transparent material to glass. There is an optimal amount of glazing that should be employed in a home. However, the determination of the window’s glazing and shading that allows for maximum summer shading and winter insulation is not trivial. [14] Many trade-offs exist; for example, too much glazing on windows (i.e. too much tint) can prevent day lighting, but if the correct materials are used, the windows can be turned into “light-shelves,” which project sunlight deep into a room. During the summer, a greater amount of glazing can reduce short-wave radiation penetration through windows, thusly reducing the cooling load. During the winter, however, too much glazing can reduce the same radiation that would create heat and reduce the heating load. Thus, an optimal amount of glazing should be determined for a building prior to undertaking any glazing project.

Although passive design features are typically easier to install and less costly, there are a number of active systems which can be incorporated into a home as well. Active water heating systems are becoming increasingly popular, and more readily available. The systems generate hot water in a renewable manner, through either an open-loop active system or closed-loop active system. Open-loop systems — also known as direct systems — use pumps to circulate household water through the collectors, thus heating the water. [15][16]These systems are quite efficient, overall economical, and relatively simple to use. While the performance of open-loop systems is quite good, it can be hindered if the water is hard or acidic. Further, the systems cannot function in areas that experience freezing temperatures for an extended period of time.

Closed-loop systems — also known as indirect systems — are different in that they pump heat-transfer fluids through collectors, and then use heat exchangers to transfer the heat from the fluid to household water. [17][18] The efficiency and performance of closed-loop systems is similar to open-loop systems. However, close-loop systems are more expensive and more complicated than open-loop systems, due to their reliance on heat-transfer fluids, which must be checked each year and changed every three to 10 years. Active systems require pumps, which require power input. Solar PV can be used to power these pumps to increase overall efficiency of the system. [19]

The Energy Star program, a joint program of the EPA and the Department of Energy, helps today’s consumers make informed purchasing decisions about a wide variety of products by labeling products which meet the program’s strict energy efficiency requirements. Many of us first became aware of the Energy Star program because of the labels on computer monitors, but the program is actually much broader than that, encompassing appliances, heating and cooling machinery, home enveloping (e.g., home sealing and roof products), home electronics, office equipment, lighting, commercial food service machinery, and other commercial products. [20]

The winter of 2008-2009 may provide the first real incentive to take personal steps toward conservation, especially in harsh climates. Home heating bills for oil or gas fuels will likely double over last winter’s, and could triple over the average for the past decade. As a result, utilities may offer programs where payments for heating costs could be spread out over time, as part of weatherization programs. Weatherization of older homes can cut home heating bills by 32 percent and save the homeowner $358 per year. [21] This will provide a real incentive to owners to reduce heat losses, just as the arrival of $4 per gallon gasoline caused significant changes in commuter travel patterns. Natural gas prices have risen in tandem with oil prices, as gas turbines became the electric power plants of choice.

The aforementioned options are but a few examples of ways that consumers can implement energy efficient technologies in their home; the truth is that options for energy conservation at the consumer-level are nearly limitless. Legislation often provides monetary incentives for installing such systems in a home, but the bottleneck often-times is the end-user. A level of personal investment is always required and many individuals do not have the will and/or the means to do so.

How are we doing?

How have we done in controlling our energy consumption growth rate? Where it averaged 3.5 percent per year over 1950-1970, it was up to 7 percent per year recently in California. But energy use per dollar of GDP has fallen more than 40 percent in 30 years (1970-2000). Figure 1 indicates energy use per capita, and per dollar of GDP from 1980 with projections to 2030. [22]

Figure 1

This chart illustrates how energy use per capita has remained relatively constant over the last three decades, and will likely continue to do so in the future. Energy use per dollar of GDP, on the other hand, has decreased considerable, and will continue to decline. This means that the nation has indeed learned to do more with less.

The overall decrease in energy use per GDP is due to the overall trend of increased energy efficiency. According to the White House’s National Energy Policy [23], US energy efficiency is improving on multiple fronts:

• New home refrigerators now use about one-third less energy than they did in 1972.

• New commercial fluorescent lighting systems use less than half the energy they did during the 1980s.

• Federal buildings now use about 20 percent less energy per square foot since 1985.

• Industrial energy use per unit of output declined by 25 percent from 1980 to 1999.

• The chemical industry’s energy use per unit of output has declined by roughly 40 percent in the past 25 years.

• The amount of energy required to generate 1 kilowatt-hour of electricity has declined by 10 percent since 1980.

Final Thoughts

In 2008, the price of imported oil exceeded $110 per barrel for the first time, sharpening the emphasis on energy conservation. [24] Because of high energy prices, awareness of energy consumption habits is as high as it has been since the 1970s energy crisis. Federal level policy has progressively pushed forward with energy efficiency and conservation measurements, but the final step is still up to the consumer — and often, the consumer does not take the necessary steps to take advantage of available incentives. Energy conservation options abound, but more consumers need to take action. Energy consumption per dollar of GDP has decreased considerably over the past couple of decades, and energy use per capita will also decrease once end-use consumers begin to actively conserve. Only then can the nation achieve increased efficiency and conservation effective enough to make a long-lasting impact on the overall development of the economy.

References

[1] A Time to Choose: America's Energy Future, Ford Foundation, www.fordfound.org, Ballinger Pub Co., 1974.

[2] Historic growth in U.S. GDP and energy consumption, Pew Center on Global Climate Change, Washington, D.C., 2000. Retrieved 28 August, 2008, from www.pewclimate.org/global-warming-basics/facts_and_figures/fig18.cfm

[3] J. Spencer, "Energy bill must not exclude nuclear from CO2 fix," The Heritage Foundation , Washington, D.C., 2007. Retrieved 26 August 2008, from www.heritage.org/Research/energyandenvironment/wm1724.cfm

[4] Legislation affecting the renewable energy marketplace, Energy Information Administration, Washington, D.C., 2008. Retrieved 26 August 2008, from www.eia.doe.gov/cneaf/solar.renewables/page/legislation/impact.html

[5] Energy Policy Act of 1992, The Encyclopedia of Earth, EOE.org, Washington, D.C., 2006. Retrieved 26 August, 2008, from www.eoearth.org/article/Energy_Policy_Act_of_1992,_United_States

[6] Weatherization assistance program, U.S. DOE Energy Efficiency and Renewable Energy, Washington, D.C., 2008. Retrieved 28 August 2008, from www.eere.energy.gov/weatherization

[7] Ibid.

[8] Solar Hot Water and Space Heating and Cooling, Energy Efficiency and Renewable Energy Network, Washington, D.C., 2002. Retrieved 27 March 2008, from www.eren.doe.gov/RE/solar_hotwater.html

[9] A. Prasad, Class notes provided for Sustainable Energy Policy: "Sunrun - A Passive Solar House Built in 1981 by Marian Peleski," University of Delaware, Newark, DE, 2008.

[10] J. Kachadorian, The Passive Solar House: Using Solar Design to Heat & Cool Your Home, Chelsea Green Publishing, 2006.

[11] Weatherization assistance program, U.S. DOE Energy Efficiency and Renewable Energy, Washington, D.C., 2008. Retrieved 28 August 2008, from www.eere.energy.gov/weatherization

[12] Ibid.

[ 13] Ibid.

[14] E. Shaviv, "Integrating energy consciousness in the design process," Automation in Construction 8(4), pp. 463-472, 1999.

[15] Weatherization assistance program, U.S. DOE Energy Efficiency and Renewable Energy, Washington, D.C., 2008. Retrieved 28 August 2008, from www.eere.energy.gov/weatherization

[16] Solar Hot Water and Space Heating and Cooling, Energy Efficiency and Renewable Energy Network, Washington, D.C., 2002. Retrieved 27 March 2008, from www.eren.doe.gov/RE/solar_hotwater.html

[17] Weatherization assistance program, U.S. DOE Energy Efficiency and Renewable Energy, Washington, D.C., 2008. Retrieved 28 August 2008, from www.eere.energy.gov/weatherization

[18] Solar Hot Water and Space Heating and Cooling, Energy Efficiency and Renewable Energy Network, Washington, D.C., 2002. Retrieved 27 March 2008, from www.eren.doe.gov/RE/solar_hotwater.html

[19] Weatherization assistance program, U.S. DOE Energy Efficiency and Renewable Energy, Washington, D.C., 2008. Retrieved 28 August 2008, from www.eere.energy.gov/weatherization

[20] Energy Star Qualified Products, Energy Star, www.energystar.gov, Environmental Protection Agency, Department of Energy, Washington, D.C., 2008. Retrieved 28 August, 2008, from www.energystar.gov/index.cfm?fuseaction=find_a_product.

[21] Weatherization assistance program, U.S. DOE Energy Efficiency and Renewable Energy, Washington, D.C., 2008. Retrieved 28 August 2008, from http://www.eere.energy.gov/weatherization/

[22] Annual Energy Outlook 2008 with Projections to 2030, Energy Information Administration, Washington, D.C., 2008. Retrieved 28 August, 2008, from www.eia.doe.gov/oiaf/aeo/graphic_data.html

[23] National Energy Policy, The White House, www.whitehouse.gov, Washington, D.C. Retrieved 28 August 2008, from www.whitehouse.gov/energy/Chapter1.pdf

[24] STEO Table Browser: Energy Nominal Prices, Energy Information Administration, Washington, D.C., 2008. Retrieved 28 August, 2008, from http://tonto.eia.doe.gov/cfapps/STEO_Query/steotables.cfm?periodType=Annual&startYear=2004&startMonth=
1&endYear=2008&endMonth=12&tableNumber=8