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United
States Energy Usage and Efficiency:
Measuring Changes Over Time
BATTLES, Stephanie J. and BURNS, Eugene M.
ENERGY INFORMATION ADMINISTRATION
Washington, D.C., United States of America
(17th Congress of the
World Energy Council, Houston Texas, September 14, 1998).
Introduction
Increasing emphasis has been placed on energy
efficiency as a vital component of the United States energy strategy. This was
evident with the passing of the Energy Policy Act of 1992 (EPACT) [1]. EPACT promotes
energy-efficiency programs such as building energy-efficiency standards, residential
energy-efficiency ratings, and energy-efficient mortgages. It also encourages investments
in conservation and energy efficiency for each of the sectors in the United States (U.S.).
EPACT also includes provisions to obtain
energy-efficiency information "with the objective of significantly improving the
ability to evaluate the effectiveness of the Nations energy efficiency policies and
programs."
The U.S. Department of Energy (DOE), universities,
trade associations, individual researchers, and others have dealt with efficiency
assessment by publishing a variety of special analyses of energy efficiency. Detailed
analyses have tended to cover limited sectors of the economy, while analyses with
comprehensive scope have ordinarily used very broad-brush efficiency indicators that have
limited explanatory power, and may be misleading. Most important, these products do not
attempt to give a single comprehensive answer to the question "How is energy
efficiency changing in the U.S. economy?"
The concept of efficiency improvement is easy to
rally behind as a general principle. Defining it, measuring it, and devising specific
programs to encourage it are much more difficult tasks. In 1993, the Energy Information
Administration (EIA) started a project to determine the most useful efficiency measures,
the most appropriate data sources, and a workable methodology for combining separate
sectors into a unified whole. Included in the project would be a historical database of
energy use and energy-efficiency indicators, an assessment of how the indicators are
changing over time, and measurements of how those efficiency changes have contributed to
the trends in total U.S. energy demand.
This paper will begin by presenting EIAs
history and role as an energy data source. Next presented will be a brief synopsis of the
developments in EIAs energy-efficiency project since it began in 1993. The following
three sections present discussions using data that will be included in the Internet
database. First will be a profile of energy use in the United States and a look at how
this usage has changed between 1970 and 1995. This will be followed by a discussion of
energy efficiency--first as to its definition and then its measurement. Two examples of
energy-efficiency indicators--national and manufacturing sector indicators will be
included in this discussion. International competitiveness makes energy use a vital
concern for some manufacturing establishments. The third category of indicators, carbon
emissions indicators, will be part of a discussion of energy use and indicators in the
transportation sector. This sector is important because energy efficiency, the
environment, and energy security are so intertwined. The paper will conclude with a
summary discussion of why EIAs energy-efficiency project has taken on new
importance.
Energy
Information Administration: Who We Are and What Do We Do
In 1977, the EIA was created as an independent
statistical and analytical agency within the U.S. Department of Energy. The EIA's mandate
in the newly-formed Department was to collect, analyze, and disseminate impartial,
comprehensive data about energy--how much is produced, who uses it, and the purposes for
which it is used. EIA's duties include collection of energy-related data from energy
suppliers and energy consumers, tabulation and analysis of energy data for publication,
and energy demand forecasting. In recent years, EIA has also produced estimates for U. S.
emissions of greenhouse gases.
As the agency charged with statistical and
analytical responsibilities for U. S. energy data, EIA has both the data and the expertise
to conduct studies of energy-efficiency measurement. EIA has access to data from a variety
of supplier and consumer surveys. Furthermore, EIA's staff has the experience needed to
make optimal use of the available data to address the complex issues of efficiency
measurement. Finally, EIA's reputation for providing unbiased results, and for
transparency of methodology, is important in dealing with energy efficiency and global
climate change issues.
Energy-Efficiency Project
Initial Development Plan
EIA has taken a slow, deliberate
approach toward defining energy efficiency and developing robust energy-efficiency
indicators. The early phase included three major steps: (1) a methodological report, (2) a
series of five workshops, and (3) the use of EIAs web site.
In October 1995, EIA published the methodological
report, Measuring Energy Efficiency in the United States Economy: A Beginning [2]. This report was called a
"beginning" because it was not intended as a definitive statement on these
issues, but rather, as a means of focusing the thinking of our customers and obtaining
their ideas. Even in the writing of the report, DOE, EIA, and outside sector specialists
furnished feedback in the form of written reviews. Draft chapters of the report were
presented for comment at seminars as soon as they were available.
Early in 1996, EIA held five all-day workshops
covering each sector discussed in the report: residential, commercial, transportation,
industrial, and the economy as a whole. The focus of the workshops was the report. The
five one-day workshops were held in Washington, D.C., in February, March and April of
1996. Over 120 experts, representing federal agencies, industry, associations, academia,
and energy-efficiency advocacy groups attended the workshops. The participants, including
engineers, economists, planners, and policy analysts, represented broad concerns as well
as varied experiences in the analysis of energy efficiency. These workshops allowed EIA to
obtain critical reviews from leading energy-efficiency researchers.
As another step in the project, EIA decided to place
the report, the workshop comments, and a conversation area on the Internet. We used the
EIA home page address as the site. A notice was sent to the workshop participants and
other interested parties. Although we received several inquiries, comments, and questions
about the initial report through our web site, the conversation area at the web site was
not successful. From those who did respond, it seemed that they were expecting either a
"true" listserver or a "chat" group.
Latest Development Plans
During the summer of 1997 the main task was to
explore ways of incorporating as many as possible of the comments received from the
report, workshops, and web site. The development of new indicators is now underway, and we
plan to use the Internet as the main method of communication. We believe that the
electronic communication will reach the maximum number of customers while conserving our
resources.
Under development is a database consisting mainly of
energy use, energy efficiency, and carbon-emission indicators. Initially, only a modest
database will be placed on the web site along with 1 to 2 page analyses on special topics.
Additions will be made when further highlights or other more complex and sector-specific
indicators become available. A query system is being developed whereby customers will be
able to easily obtain data from the main tables in the database. As an additional method
of communication, we will print booklets and brochures presenting highlights of the
database and the most important findings.
Energy Use in the United States
United States Energy Use Relative to World Use
I n 1995, the U.S., with a population of 263 million
people, used an estimated 95,300 PJ of primary energy. This estimate represents 25 percent
of the world energy use while the U.S. has only 5 percent of the world population. By
comparison, Japan--ranked 4th in energy use--used 6 percent of the world energy
while having 2 percent of the world population [3].
Many factors affect the quantity of primary energy
used by a country. Primary energy includes not only the energy directly consumed by the
end-users of the energy, but also the losses associated with the generation and
transmission of electricity. Thus, countries that are electricity-intensive will tend to
have large primary energy requirements. In 1995, the U.S. used approximately 27 percent of
the worlds electricity versus Japans 7 percent.
The level of economic production also affects the
level of energy use. In 1995 the U.S. Gross Domestic Product (GDP) at market exchange
rates was the highest of any country-- 5.5 trillion dollars (1987 dollars). The next
largest economy, Japan, had a GDP of 3.0 trillion dollars (1987 dollars). Land area is
also directly related to the level of transportation demand. For example, while the U.S.
ranks 3rd in population and Japan ranks 9th, the population density
for Japan (318/km2) is more than 10 times that of the U.S. (29/km2).
The U.S. has more than three times as many motor vehicles as Japan [4].
Energy Use in the United States: a Profile
In 1995
fossil fuels (petroleum, natural gas, and coal) accounted for 85 percent of the primary
energy consumed in the U.S. Petroleum accounted for 38 percent of the energy used in the U.S. (Figure 1a). This
was equivalent to 18 million barrels per day, with 12 million barrels per going to
the transportation sector, mostly for motor gasoline [5]. Natural gas accounted for
25 percent (23,400 PJ) of the energy used in the U.S. Natural gas was used mainly in the
industrial sector (45 percent of the natural gas used), followed by the residential sector
(22 percent), and then the commercial sector (14 percent). Coal, accounting for 22 percent
of energy use (20,800 PJ), is heavily used by the electric utility industry. The electric
utility industry consumed 86 percent of the coal used in the U.S. In 1995, electric
utilities consumed 33,416 PJ of energy, of which 54 percent was coal [6].
Electricity
can be generated using conventional energy sources such as coal, but also from other
sources such as nuclear energy and hydropower. This type of generated electricity accounts
for 15 percent of energy use in the U.S. To measure the full effect of electricity use in
the major end-use sectors (industrial, residential, commercial, and transportation), we
need to take into account the losses incurred in the generation and transmission and
allocate these losses to each of the sectors. Taking losses into account, in 1995
electricity use in the U.S. represented almost as much energy content as did petroleum
(for purposes other than generating electricity). About 35 percent of all end-use energy
(approximately 33,500 PJ) was electricity [7].
In 1995,
the U.S. industrial sector used 36,376 PJ of energy--38 percent of total U.S. energy consumption (Figure
1b). Manufacturers consumed most of this energy (about 75 to 80 percent).
(Nonmanufacturing industrial users in mining, construction, agriculture, fisheries, and
forestry consumed the rest.) Electricity, including generating losses, accounted for 32
percent of the energy use (mainly to run motors). Natural gas accounted for approximately
another 30 percent of energy used. In the manufacturing sector natural gas is used mainly
for process heating, boiler fuel, and as a feedstock. In the industrial sector, including
manufacturing establishments, petroleum accounted for 25 percent of the energy used. In
manufacturing establishments, the petroleum is used mainly for process heating and boiler
fuel [8].
Of all
the energy sources used in the transportation sector, motor gasoline is used the most,
accounting for 61 percent of the 25,397 PJ used in this sector. Distillate fuel accounted
for 18 percent and jet fuel for 13 percent, of transportation energy use.
Electricity
and natural gas are the main energy sources used in U.S. households. About one half of the
electricity is used for appliances such as washers, television sets, etc. while most of
the natural gas is used for space and water heating. In 1995, the residential sector used
20 percent (19,051 PJ) of the energy used in the U.S.
In 1995,
the commercial sector used 14,711 PJ--the least of any of the four end-use sectors.
The commercial sector uses mainly electricity, followed far behind by natural gas, (72
percent versus 22 percent). Almost one-half of the electricity is used for lighting while
most of the natural gas is used for space heating [9].
Energy Use in the United States: 1970 to 1995
Before the 1970s the United States experienced
a time of falling energy prices and ample supplies of petroleum. As economic activity
(measured by Gross Domestic Product (GDP)) increased, so did the consumption of energy (Figure
2). In 1973, crude petroleum prices shot up by 400 percent. At first short term
effects, such as lowered thermostats and reduced driving, were common, but their overall
effects on demand were small. While these transient actions were taking place, later to
subside, other, more fundamental changes were working their way into energy-using
processes. As these long-term changes in energy use characteristics and demand
characteristics became permanent, the relationship between GDP and energy consumption
weakened. The adoption of automobile and appliance standards, a shift in manufacturing
away from energy-intensive processes, the growth of the service sector, and the
introduction of energy-efficient appliances were just some of the more permanent changes [10]. In the early 1980s the growth of
economic activity outpaced the demand for energy.
At the same time, a growing electrification, led by
the commercial sector, has taken place (Figure 3) in the U.S. Electricity use grew by 53
percent between 1980 and 1995 in the commercial sector, and by 47 percent in the U.S. as a
whole. With the growth of the service sector relative to manufacturing, the commercial
building stock increased. In addition, the use of office equipment--from computers to copy
machines--grew rapidly. In the residential sector the increased use of heat pumps for both
space heating and air conditioning in the residential sector has been one of the factors
leading to large increases of electricity use. This was especially true in the new homes
constructed in the South, which experienced 30 percent growth in the number of housing
units between 1980 and 1995. New homes also have been getting larger and households have
been using more appliances, and multiples of the same appliances, such as televisions and
computers [11]. Although
the increase was not as large (13 percent), the industrial sector also experienced a
growth in the use of electricity between 1980 and 1995. In this sector, there has been a
shift from some of the more energy-intensive industries, such as the primary metal
industries. This shift has not only been toward less energy-intensive industries, but also
toward those that heavily use motors--the major use of electricity in the manufacturing
sector [12].
As the use of electricity has increased, there has
been a strong push, with California leading the way, to restructure the electric utility
industry. In March 1998 the Administration presented the Comprehensive Electricity
Competition Plan. This plan proposes consumer choice of a power supplier by January 1,
2003. The speed of total restructuring or the effect of electricity restructuring on
electricity demand is difficult to predict. Many debates are taking place on topics such
as whether customers will see lower electricity prices, the fate of renewable energy, and
whether energy-efficiency technologies will continue to be developed and implemented.
Energy-Efficiency Indicators
Definition
There is no single commonly-accepted definition of
energy efficiency. At one level, energy efficiency is a value-laden concept, referring to
the relative thrift or extravagance with which energy is used to provide goods or
services. From a more technical perspective, an increase in energy efficiency can be said
to have occurred when either energy inputs are reduced for a given level of service, or
there are increased or enhanced services for a given amount of energy inputs.
Energy intensity is defined as the ratio of energy
consumption to some measure of demand for energy services. Energy intensity measures are
often used to measure energy efficiency and its change over time. However,
energy-intensity measures are at best a rough surrogate for energy efficiency. This is
because energy intensity may mask structural and behavioral changes that do not represent
"true" efficiency improvements such a shift away from energy-intensive
industries. The choice of a measure of demand for energy services (a "demand
indicator") in efficiency analysis is critical.
Although it is difficult to equate energy efficiency
to a single intensity measure, or set of measures, some form of energy intensity is often
the best we can do with available data. Indicators of energy intensity are useful, but we
must remember that the underlying components are critical to interpretation. Without a
structural context, the indicators can be misleading. The structural component of
intensity is important because it shows where policy might or might not be directed.
When EIA asked participants in the energy-efficiency
workshops to define "energy efficiency," participant definitions reflected two
different perspectives: either a service perspective or a mechanistic, strict intensity,
perspective. Some participants believed that energy-efficiency indicators could measure
some kind of economic well-being, and suggested that a wide range of indicators would
offer insight into the "ordinary business of life" and the relationships,
causes, and opportunities in observed trends. One concept of efficiency is a strict
technological (equipment-based) concept. This concept cannot be strictly measured by broad
intensities, because intensities tend to carry structural and behavioral components.
Alternatively, some participants believe that differentiating between intensity and
efficiency is senseless.
The central question in the analysis of energy
efficiency may really be "efficient with respect to what?" Measurement of energy
efficiency always relates to the specific policy objectives at stake. Otherwise, why
should we care how efficient we are? Are we concerned specifically about economic well
being, higher productivity, increased employment and incomes, resource conservation, or
improved environmental quality? Different answers call for different indicators.
Consequently, the appropriate indicator is dependent on the policy objective. For example,
if the policy objective concerned the environment, then the intensity indicator would
involve carbon emissions. From the global warming perspective, the absolute carbon
emissions are obviously most important, and energy intensity is not relevant. On the other
hand, if economic productivity is the policy objective, then energy expenditures per
dollar of GDP might be a more suitable indicator.
United States Indicators
A variety of potential efficiency indicators exist
for each end-use sector. (The next section (Section 5.3) will examine various indicators
that have been proposed for the manufacturing sector.) However, whatever choices are made
for individual sectors, at some point summary measures for the nation as a whole are
needed. Obvious uses for national energy-efficiency indicators are policy formulation,
assessment, and justification.
Measuring energy efficiency in the overall economy
is even more complex than in the individual sectors. Measures of demand tailored to
particular end-use sectors are likely to be inappropriate for the other sectors. EIA is
considering two approaches toward the development of aggregate national indicators.
The first approach is to construct energy intensity
measures using simple indicators of demand: population and GDP. Intensity measures
constructed using these simple indicators can be useful for analysis. For example, the
trend in energy use per person reflects historical energy price reactions, while energy
use per dollar of GDP does not. The trend line for energy per
dollar of GDP (Figure 4) shows a continuing
reduction in energy consumption per dollar of GDP since 1970-- with a 19 percent reduction
between 1980 and 1995. The story is different on a per-capita basis. Before 1980, and
during the times of the "oil price shocks," short-term reactions to price
changes can be clearly seen. Energy per capita after 1980 did not continue to decline but
stayed rather flat between 1980 and 1995, reflecting favorable energy prices.
Besides the simple aggregated indicators
demonstrated here, EIA is considering one further aggregation option, the construction of
an energy-efficiency index. The relative nature of energy efficiency lends itself to the
development of indexes. Individual sector indexes, suitably weighted, could be aggregated
to form a national index.
Alternatively, a market-basket index, similar to the
Consumer Price Index (CPI), is under consideration. A market-basket index starts with a
fixed set of energy services. Compared over time to an engineering-improvement market
basket of those same services, technical efficiency could be gauged. This approach
captures the price-induced behavioral substitution shifts among basket items. However, a
market-basket approach will share some of the same problems that the CPI does, such as the
substitution effect--as the price of one good increases, the demand for a cheaper
substitute increases also.
Manufacturing Sector Indicators
Two major users of industrial indicators are the
academic and the research and development communities. Efficiency indicators may be used
for policy analysis and some forecasting. An additional policy-oriented perspective could
be considered, however, for identification of opportunities or target markets within the
sector. Are we on a trend? Will opportunities present themselves or have we already found
them all? Long-term industrial sector forecasting could use some type of end-use
efficiency indicators.
Most indictors require a disaggregated approach,
with more detail than 4-digit standard industrial classification (SIC). Ultimately, we
need to look at indicators by process. However, the data needed to undertake such a highly
disaggregated approach are unobtainable, either due to EIA's resource constraints or
because the data are inherently difficult to obtain. Although the industrial sector
includes mainly manufacturing industries, data on the other industries within the sector
are virtually nonexistent. EIA does collect manufacturing data through the Manufacturing
Energy Consumption Survey (MECS). The MECS data are collected every four years, but only
by 4-digit SIC for the nine Census divisions. The only demand indicators with
establishment data available for any underlying analysis are the indicators based upon
MECS data. These indicators are the value of shipments, the value of shipments adjusted
for inventory (value of production), and the value of production adjusted for capacity.
From an engineering perspective, efficiency measures
should use physical measures of output, not economic value. However, although limited data
are available for some industries, such as the aluminum or lumber industries, physical
output data are not available for most industries. In the EIA database under development,
we plan on including as many intensity measures using physical measures as possible.
However, we will have to use a measure of economic value for most industries and
especially for the U.S. as a whole. Economic values of output or demand will be
problematic in an international context when trying to compare countries using different
currencies.
In the development phase of this project we examined
several measures of economic values as potential demand indicators: gross output (GO),
gross product originating (GPO), industrial production, value added, value of shipments
(VS), VS adjusted for inventory changes (value of production (VP)), and VP adjusted for capacity. Figure
5 shows examples of three of these, GO, GPO, and VS. Between 1988 and 1994, energy
intensity did seem to fall, from 1 percent (using the GPO demand indicator) to 9 percent
(using GO as the demand indicator).
In December 1996, a study comparing physical and
economic measures was undertaken by the U.S. Department of Energy--Measuring Industrial
Energy Efficiency: Physical Volume Versus Economic Value. Although this study
advocates the use of physical measures wherever feasible, it states that the value of
production demand indicator is the most desirable in the measure of energy efficiency. As
the report states,
"Given that it is less likely to exaggerate
swings in energy efficiency in the short run, and that it more closely matches growth
rates in the long run than other value-based demand indicators, in the absence of serious
coverage or specialization problems, value of production appears to be the most desirable
value-based demand indicator for use in a measure of energy efficiency [13]."
EIA plans to use the value of production as the
demand indicator. Additionally, the value of production will be adjusted for the changes
in manufacturers internal mix of products produced during these years, and for the
changes in the technologies and processes used to produce them. As a result of the
workshop comments, the EIA energy-efficiency database will include indicators based on
end-use data, primary and site energy, purchased energy and expenditures, and separate
energy sources, by 2-digit and 4-digit SIC.
Transportation Sector Indicators
At the time that DOE was founded in 1977, U.S.
energy issues were defined in terms of energy supply and energy security. Analysts were
concerned that the U.S. had become too reliant on uncertain foreign sources of oil.
Imports supplied 46.5 percent of petroleum consumption in 1977. Over a third of the
petroleum consumed in the U.S. originated in OPEC countries [14].
After dropping to a post-1970's low of 27.3 percent
in 1985, imports again supply almost half of the U.S. petroleum consumption [15]. However, the focus of energy-related concerns has shifted to
the environment. Concerns about energy-resource depletion have largely been displaced by
concerns about carbon emissions associated with energy use. The 1992 Rio Agreement and,
especially, the 1997 Kyoto Protocol have heightened interest in the emissions of
greenhouse gases.
To discuss emissions targets, a background
understanding is needed on how energy is being consumed and the trends in energy
consumption, as well as the associated emissions. The use of petroleum in transportation
will serve as a simple example.
Since the 1970's, the role of petroleum has become
narrower and more focused on serving the needs of the transportation sector. Electric
utilities and, to a lesser extent, residential and commercial users, have moved away from
petroleum as an energy source (Figure 6). Industrial use has remained fairly level,
but represents a declining share of total petroleum consumption. However, the use of
petroleum for transportation has more than compensated for declines in the other sectors.
Transportation, which accounted for a bit over half of petroleum consumption in the
1970's, now accounts for over two-thirds. Ninety-seven percent of the energy consumed for
transportation in 1995 was petroleum.
Overall, while transportation energy consumption per
capita did not change greatly (up 6 percent) between 1980 and 1995, transportation energy
consumption increased by more than 23 percent (Figure 7). The increase was not uniform.
Transportation energy consumption peaked in 1978, at 21,145 PJ (95.2 GJ per capita). The
1978 level of consumption not reached again until 1986, although consumption per capita
has so far remained below the 1978 level. Consumption has generally been rising (with a
dip in 1991) through 1995 [16].
Carbon emissions have tracked steadily along with
energy consumption. The trend lines for energy consumption and carbon emissions will
remain virtually identical until nonpetroleum fuels emerge as significant sources of
transportation energy. In 1995, the carbon emissions related to transportation energy use
amounted to 457 million metric tons, almost a third of total U.S. emissions [17].
Several factors contributed to the increased demand
for transportation energy (Figure 8). First, the U.S. population grew by 16
percent from 1980 to 1995. Second, the U.S. GDP increased by 46 percent over the 15-year
period. GDP per capita rose 26 percent, so that Americans, on average, were wealthier.
This increased wealth permitted an increase in purchases of sport-utility vehicles that
consumed more energy per distanced traveled than do passenger cars. Finally, the number of
motor vehicles in use increased by 27 percent. Motor vehicles, a large component of
transportation energy use, are overwhelmingly petroleum-fueled. The number of motor
vehicles per thousand persons increased from 713 to 778. Within the motor vehicle stock,
the passenger car share declined from 80 percent to 67 percent, as light trucks became
increasingly popular for personal transportation [18].
Population, GDP, and the number of vehicles all are
gross indicators of the demand for transportation. More detailed measures include the
distance traveled per vehicle and the quantity of energy required to travel a given
distance. After dipping slightly in response to price shocks of the 1970's, starting from
1980, the distance traveled per year by the average motor vehicles increased steadily.
However, vehicles used less energy to travel a given distance throughout the 1980's (Figure 9). After
declining from the late 1970's to 1990, the trend toward less fuel used per unit distance
flattened out in the 1990's. The two trends, toward more distance per vehicle and less
energy per unit distance, have opposite effects on energy consumption and on the
associated carbon emissions. Vehicles required less energy to travel a given distance, but
they were driven greater distances.
This section has presented broad indicators of
transportation energy use. These broad indicators do not do justice to the diversity of
transportation sector (which includes both passengers and freight, and various modes of
transport). Nevertheless, these indicators have led to some insight into the activities
responsible for increases in transportation energy use and emissions. The indicators also
highlight structural and behavioral trends in population growth, motor vehicle stock mix,
and driving patterns. These trends need to be offset, either by efficiency gains or by
changes in the transportation fuel mix, if carbon emissions in the transportation sector
are to be reduced.
Summary
Recent developments have given new emphasis to the
analysis of energy efficiency in the U.S. The Energy Policy Act of 1992 specifically
requested the development of information on energy efficiency. Furthermore, on-going
international negotiations regarding global climate change have highlighted the crucial
role of energy efficiency in meeting possible treaty commitments without sacrificing
lifestyles.
The Energy Information Administration (EIA), the
independent statistical and analytical agency within the U.S. Department of Energy, began
its energy-efficiency analysis in 1993. Initial efforts resulted in a methodological
report (1995), a series of workshops (1996), and the establishment of an energy-efficiency
area on EIA's web site (1996-present). EIA is now moving on to the next phase of
energy-efficiency analysis, incorporating comments, suggestions, and experiences gleaned
from the initial effort and subsequent research.
The U.S., with 5 percent of the world's population,
uses 25 percent of the world's energy. Factors associated with this high rate of energy
use include a high level of electrification, the world's highest GDP, and extensive land
area. The U.S. consumed 95,300 PJ of energy in 1995. The industrial sector accounted for
38 percent of that consumption, followed by the transportation sector with 27 percent of
the consumption. The residential and commercial sectors consumed the rest.
Several significant trends can be detected in U.S.
energy consumption over the period from 1970 to 1995. Price shocks during the 1970's led
to long-term changes in U.S. energy consumption patterns, and weakened the relationship
between increases in energy consumption and increases in GDP. Except in the transportation
sector, petroleum use has declined or remained flat, while electricity use has accounted
for an increasing proportion of end-use consumption. It is too soon to tell the
consequences of the restructuring of the electricity industry.
The definition and measurement of energy efficiency
are not easy tasks. Energy-intensity measures are frequently used a surrogates.
Energy-intensity measures have shortcomings, however, in that they can confound energy
efficiency changes with other, structural and behavioral, changes. Ultimately, the choice
of energy-efficiency indicators should be dictated by the purposes of the analysis.
The definition of indicators for individual sectors
may be difficult, but further problems emerge when constructing indicators for the U.S. as
a whole. Two approaches are being considered. One approach is to construct national
indicators based on simple measures of demand, such population and GDP. A second approach
would be some form of indexing.
Examples of the problems and uses of efficiency
indicators are presented for two sectors, manufacturing and transportation. The
manufacturing example illustrates the problems involved in choosing demand and efficiency
indicators. Linkages among energy security issues, carbon emissions, and energy efficiency
are demonstrated for the transportation sector.
In conclusion, EIA is taking a slow, deliberate, and
thorough approach in the development of an Internet database of energy-use,
energy-efficiency, and carbon-emissions indicators. By taking this approach, EIA will be
able to produce indicators, within resource limits, that are not only robust, but also EIA
will be able to update the indicators as new data are available.
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Laboratory, December 1996.
14. "Annual Energy Review 1996," pub. DOE/EIA-0384(96), Energy Information Administration, July 1997.
15. "Annual Energy Review 1996," pub. DOE/EIA-0384(96), Energy Information Administration, July 1997.
16. "State Energy Data Report 1995," pub.
DOE/EIA-0214(95), Energy Information Administration, December 1997.
17. "Emissions of Greenhouse
Gases in the United States 1995," pub. DOE/EIA-573(95), Energy Information
Administration, October 1996.
18. "Annual Energy Review 1996," pub.
DOE/EIA-0384(96), Energy Information Administration, July 1997.
Contacts
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questions on this topic may be directed to:
- Stephanie
Battles
- Stephanie.Battles@eia.doe.gov
- (Phone:
(202) 586-7237)
- FAX:
(202) 586-0018
Contact Us
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