Energy Efficiency: A U. S.
Summary. The U. S. National Academies issued a report, “Real Prospects for energy Efficiency in the United States
Introduction. Global warming is currently occurring, due to the release of ever-increasing amounts of greenhouse gases into the atmosphere. This conclusion is broadly accepted among the scientific community, and understood by much of the American public at large. Most greenhouse gases arise from mankind’s burning of fossil fuels for energy, starting with the industrial revolution in the nineteenth century.
Among developed, industrialized countries of the world, the United States
Energy Efficiency. An important, but not widely recognized, component of plans to minimize emissions of greenhouse gases is increasing energy efficiency. By this is meant setting in place projects and procedures that lead to more effective use of energy resources that are already in use. That is, efficiency leads to more of a useful energy product being derived, per unit of the fuel consumed.
The National Academies Report. The U. S. National Academy of Engineering, a component of the National Academies, issued the report “Real Prospects for energy Efficiency in the United States
The report was prepared in response to a charge to the National Academies as part of the larger task directed to America America
Main Results. The total amount of energy used in the U. S. in 2008 is given by major economic sector in the table below, in units of quadrillion (1015) Btu (British thermal units; the amount of energy needed to heat 1 pound of water by 1ºF, about 1,055 joules).
Sector | Quads | Pct (%) |
Transportation | 28.0 | 28 |
Residential | 21.6 | 22 |
Commercial Buildings | 18.5 | 19 |
Industry | 31.3 | 31 |
TOTAL | 99.4 | 100 |
Source: Summary, Real Prospects for Energy Efficiency in the United States
http://books.nap.edu/catalog/12621.html; citing U.S. Energy Information Agency Annual Energy Outlook 2008.
The panel assessed each of these sectors in order to identify the ways that savings in energy used could be accomplished, and by how much. The following table presents the report’s estimates of energy savings that can be achieved by two future dates, and according to two frameworks, a conservative estimate and an optimistic estimate. (Note that there is no analysis for heavy-duty vehicles.)
Energy savings in quads relative to the U. S. Energy Information Agency Annual Energy Outlook 2008 (or a similar scenario prepared for Transportation).
Conservative | Conservative | Optimistic | Optimistic | |
Sector | 2020 | 2030 | 2020 | 2030 |
================ | ====== | ====== | ====== | ====== |
Buildings, primary (source) electricity | 9.4 | 14.4 | 9.4 | 14.4 |
Residential | 4.4 | 6.4 | 4.4 | 6.4 |
Commercial | 5.0 | 8.0 | 5.0 | 8.0 |
Buildings, natural gas | 2.4 | 3.0 | 2.4 | 3.0 |
Residential | 1.5 | 1.5 | 1.5 | 1.5 |
Commercial | 0.9 | 1.5 | 0.9 | 1.5 |
Transportation, light-duty vehicles | 2.0 | 8.2 | 2.6 | 10.7 |
Industry, manufacturing | 4.9 | 4.9 | 7.7 | 7.7 |
TOTAL | 18.6 | 30.5 | 22.1 | 35.8 |
Source: Summary, Real Prospects for Energy Efficiency in the United States
In the absence of savings arising from energy efficiency measures, the report estimates that energy consumption would be 111 quads by 2020, and 118 quads by 2030. These results lead to the important conclusion, according to the report, that under the optimistic estimate, by 2030 the energy savings could be 30% below the forecast usage without the efficiency measures (26% below the forecast usage by the conservative estimate).
Main Findings. The report’s most comprehensive results are summarized here, just below. (Details and some other material appear at the end of this post, after Conclusions.)
First, technologies to achieve significant gains in energy efficiency exist at this time, or are reasonably expected to become practical, in the period up to 2020, or 2030. These efficiencies would permit major savings in energy usage, and corresponding savings in costs to end users. These have been summarized in the preceding section. The “business-as-usual” reference trend against which these savings is assessed are those projected in the U. S. Energy Information Agency’s (EIA) Annual Energy Outlook, 2008. To the extent that prices for using energy increase by market forces, or that governmental policies are put in place that increase the price of energy, these efficiencies should be readily accomplished (see the table above) and the corresponding savings achieved. The size of the energy savings that can be achieved is considered large enough to reverse the need to install new electricity generating facilities. The investment involved in achieving energy efficiency is far less than needed for new generation facilities, and are implemented more rapidly.
Second, if all modalities for achieving energy efficiency in the buildings sector alone were to be implemented, there would be no need to add new net electricity generating facilities. This comes about because the efficiency savings in the table above from the buildings sector to 2030 exceed the forecast by the EIA for anticipated needs for new generation. The report assesses barriers that could arise and that hinder full achievement of these efficiencies. These include high initial costs, alternative uses competing with investment in efficiencies, volatility of fuel prices which inversely affects incentives to proceed, as some examples. On the other hand, the report cites other U. S. STAR ® program.
Third, the report recognizes that significant barriers to installing energy efficiency exist, and must be overcome. To achieve this, widespread support from public and private institutions needs to be marshaled. Examples of programs in large states such as California New York
Fourth, buildings and infrastructure, once in place, have long lifetimes that lock in the features used in their construction. For this reason it is important to carry out capital projects with an eye to incorporating known energy efficient design features right away.
Conclusions. Energy efficiency programs can provide significant reductions in energy usage in the near term in return for reasonable expenditures of funds invested up front. Depending on the sector of the economy and the technology or method that is put in place, as much as 26-30% savings in energy use could result by 2030. This broad conclusion, effective at the national level, indeed internationally, is reinforced by the report in the immediately preceding post on energy efficiency retrofits in public buildings. Frequently the costs of instituting energy efficiency measures are less than those needed for constructing new energy facilities that are based on renewable energy or that incorporate new technologies for energy utilization.
Carbon dioxide (CO2), an important greenhouse gas, accumulates in the atmosphere because it is a stable atmospheric component, not subject to degradation. Its lifetime is measured in centuries, if not longer. Currently CO2 concentrations are at about 390 parts per million (ppm) and increasing by about 2 ppm per year because humanity continues to burn fossil fuels at a high rate. We can think of the atmosphere as being like a CO2 bathtub, filling with new CO2 from the faucet each year, and with minimal reduction in the level of CO2 by exiting the drain. This increase worsens the effects of global warming with each passing year. The information presented here argues strongly that implementing energy efficiency programs should be a major part of our efforts to limit emissions of greenhouse gases.
Details.
Historical Review of Policies and Programs. The report reviews energy efficiency efforts already in place. A) Vehicle fuel economy standards have been increased in the U. S. U. S.
D) Federal research and development has led to important improvements, many of which have been successfully commercialized. E) Various American federal tax incentives have been enacted, and many have lapsed, encouraging homeowners to install energy-saving retrofits. These are complemented in the U. S. U. S. STAR ® program that focuses consumers on home appliances that are rated to use less power.
The American Energy Economy in 2009. The EIA displays energy flows from its sources through its uses and ending with its products and waste in a comprehensive energy flow chart, shown for 2009 in the following graphic. The main reason for showing this graphic here is explained in detail in the legend to the graphic.
Energy flows in the U. S.
Source: U. S. Lawrence Livermore
The important conclusion is obtained by comparing the light gray box for rejected energy (i.e., energy wasted as heat and lost to the environment) at the upper right, 54.64 quads, with the dark gray box for energy services (energy applied for a useful purpose), 39.97 quads. This shows that useful energy captures only 42% of the total energy present in fuels and other energy sources input at the left of the flow diagram. Since most of the input energy derives from fossil fuels, this leaves ample opportunity for capturing additional useful energy, and reducing wasted energy, by increasing the efficiency with which energy is used. Most of the losses occur in electricity generation (26.1 quads; 48% of total rejected energy) and transportation (20.2 quads; 37% of total rejected energy). This increase in efficiency would lead to economy-wide reductions in the emission of greenhouse gases.
Buildings. As seen from the first table above, residential and commercial buildings combined use about 40% of the total energy consumed in the U. S. Of this about ¾ is provided by electricity, and most of the remainder from natural gas. This energy is devoted primarily to heating, cooling and ventilation, and to lighting. Efficiency savings are projected to accumulate at a rate of about 1.2% per year for electricity and 0.5% per year for natural gas, leading to a cumulative savings rate of 25-30% per year over the next 20-25 years. (Not included in these estimates is additional saving by integrated design of buildings that combine efficiencies between the uses itemized above with enhanced structural design. Examples of commercial buildings incorporating such features have resulted in energy savings as high as 50%.) Other improvements in several areas are being developed that could contribute even more energy savings. These new developments could become widely practiced under favorable policies.
Factors cited in the report that could impede putting energy efficiency in operation include public reluctance to undertake retrofitted efficiencies and the long building lifetimes mentioned earlier. In spite of these factors, placement of energy efficiency could become more favorable with higher energy prices, increased awareness of the hazards of global warming, increased willingness by the public and by business to act to reduce greenhouse gas emissions, and a growing appreciation of environmentally-friendly building practices.
Transportation. The transportation sector encompasses vehicle transport, rail, air and shipping. This sector consumes 28% of all the energy used in the U. S.
The report emphasizes that important reductions in greenhouse gas emissions from transportation will come from incremental improvements, rather than from a few major changes in technology. The internal combustion engine (ICE) and its fuel delivery infrastructure is well established in transportation, and is difficult to minimize or eliminate in the short term.
Improvements in passenger vehicles include reducing their weight, enhancing the efficiency of the engine and drive train, and reducing losses in moving the vehicle on the road. Many of these changes are currently available or within reach, but not widely deployed. A concern is that any gains in efficiency from measures such as these would be diverted into producing larger and/or more powerful cars, thus defeating the purposes of reducing emissions in the first place. The consuming public in the U. S.
The report foresees that improvements such as the above, and others, could produce reductions in fuel consumption, and in emissions of greenhouse gases, from today’s levels by 2035 to the range of 55-65% of today’s levels, depending on the type of ICE. Hybrid-electric vehicles reduce fuel consumption to about 20-40% of present levels, and greenhouse gas emissions to 35-45% of today’s levels (which accounts for generating electricity from fossil fuel-driven power plants). Fully battery-powered electric vehicles and fuel cell-powered vehicles consume no petroleum fuel directly, but emit greenhouse gases as for hybrid vehicles in view of their dependence on electricity for charging batteries or for manufacturing hydrogen fuel. Only a major shift to renewable electric generation could significantly affect this factor.
In contrast, establishing non-ICE alternatives such as electric-powered or hybrid-electric cars, or fuel cell powered cars using, for example, hydrogen, is poorly advanced at this time. Aspects of technology, such as batteries and on-board hydrogen storage, are still under development, and infrastructure to support these alternatives is largely absent. The report points out that timelines for deploying new technologies are long, in view of development, sales, installing infrastructure, and removing existing vehicles, which have long lifetimes, from service.
The report notes that heavy trucks may experience 10-20% improvements in fuel economy. Airplanes, which have undergone major improvements in the 20th century, may still gain up to 35% in fuel economy; but it is widely agreed that air transport will be expanding considerably in future years, offsetting gains in efficiency. Ships and railroads are already highly efficient, with little further gain anticipated.
The report points out that a systemic analysis of transportation in the U. S.
Industry. Manufacturing and other industries, including petroleum refining, consumed 31% of energy used in the U. S. U. S.
Beyond 2020, more revolutionary advances are expected in areas such as new sources for heat and power, as well as more efficient technologies for production that capitalize on advances in nanotechnology and micro-manufacturing, as well as more effective resource recovery and reuse. Other examples include advanced sensors and controls, microwave processing of materials, use of nanotechnology to provide novel ceramic coatings, and high temperature membrane separation processes.
The report notes that in many industries for which energy costs are not high, the incentive to undertake energy efficiency projects is low, compared to competing uses for capital such as human resources, new product research and development, and the need to comply with agency regulations. Factors that favor increased energy efficiency include high and fluctuating costs for fuels and competitive pressure to reduce overhead and costs of manufacture.
© 2011 Henry Auer
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