Executive Summary
Energy End Uses Ranked by Energy Consumption, 1989
Source: Energy Information
Administration, Office of Energy Markets and End Use, Forms EIA-871A through F of the 1989
Commercial Buildings Energy Consumption Survey.
The demand for energy in U.S. stores, offices, schools, hospitals, and other commercial
buildings has been increasing. This report examines energy intensities in commercial buildings
for nine end uses: space heating, cooling, ventilation, lighting, water heating, cooking,
refrigeration, office equipment, and "other." The objective of this analysis was to increase
understanding of how energy is used in commercial buildings and to identify targets for greater
energy efficiency which could moderate future growth in demand.
The source of data for the analysis is the 1989 Commercial Buildings Energy Consumption
Survey (CBECS), which collected detailed data on energy-related characteristics and energy
consumption for a nationally representative sample of approximately 6,000 commercial
buildings. The analysis used 1989 CBECS data because the 1992 CBECS data were not yet
available at the time the study was initiated. The CBECS data were fed into the Facility Energy
Decision Screening (FEDS) system, a building energy simulation program developed by the
U.S. Department of Energy's Pacific Northwest Laboratory, to derive engineering estimates of
end-use consumption for each building in the sample. The FEDS estimates were then statistically
adjusted to match the total energy consumption for each building.
This is the Energy Information Administration's (EIA) first report on energy end-use
consumption in commercial buildings. This report is part of an effort to address customer
requests for more information on how energy is used in buildings, which was an overall theme
of the 1992 user needs study. (See User-Needs Study for the 1992 Commercial Buildings Energy
Consumption Survey, DOE/EIA-0555(92)/4, Washington, DC, September 1992.) The end-use
data presented in this report were not available for publication in Commercial Buildings Energy
Consumption and Expenditures 1989 (DOE/EIA-0318(89), Washington, DC, April 1992).
However, subsequent reports on end-use energy consumption will be part of the Commercial
Buildings Energy Consumption and Expenditures series, beginning with a 1992 data report to be
published in early 1995.
Since EIA is publishing commercial energy end-use estimates for the first time, readers are
urged to provide comments and suggestions for the improvement of 1992 and future end-use
energy estimates.
Overview of Energy Consumption in Commercial Buildings
In spite of the gains in energy efficiency made since the 1970's, economic expansion and
increases in energy-consuming services during the 1980's caused a net increase in energy
consumption in the commercial sector. Energy demand in the commercial sector grew during the
1980's by 1.0 percent a year, second only to the transportation sector's rate of 1.4 percent a
year. In contrast, energy demand in both the residential and industrial sectors declined during the
1980's. Commercial buildings in 1989 consumed almost 6 quadrillion Btu of energy for end
uses and ran up an energy bill of over $70 billion.
By type of building, the three largest energy users were (a) office buildings (1.2 quadrillion
Btu); (b) department stores, drugstores, gasoline stations, post offices, and other mercantile and
service buildings (1.0 quadrillion Btu); and (c) education buildings (0.7 trillion Btu).
Of the various end uses, space heating accounted for the largest share of consumption (35
percent), followed by lighting (18 percent), water heating (9 percent), office equipment (7
percent), cooling (5 percent), ventilation (5 percent), cooking (5 percent), and refrigeration (3
percent).
Of the four major energy sources (electricity, natural gas, fuel oil, and district heat) consumed in
commercial buildings in 1989, electricity accounted for almost 50 percent of all the energy
delivered to commercial sites, while natural gas accounted for 36 percent of site consumption.
Natural gas space heating and electric lighting were thetwo largest consumers of site energy.
However, the amount spent on electric lighting was more than double the amount spent on
natural gas for all end uses, due to the higher price of electricity compared with the price of
natural gas.
An "energy intensity" is the ratio of energy consumption to a measure of the demand for energy
services. A common measure of energy intensity is the ratio of the amount of energy consumed
for the building as a whole or for a particular end use to the square footage of a building's
floorspace. More precise measures of energy intensity can account for such factors as building
operating hours or weather conditions. Intensity ratios allow buildings to be compared in terms
of energy consumption, even though they are of different sizes, are located in different climates,
and have different operating hours.
Analysis of energy intensities for the buildings in the 1989 CBECS showed that:
-
The highest energy intensities per square foot were found in buildings constructed in the 1960's,
with buildings constructed in the 1980's continuing a trend towards lower intensities.
- Buildings in the coolest climates had the highest energy intensities per square foot because
of their greater demand for space heating, despite their lower demand for cooling.
- Each type of commercial building had a different end-use intensity profile, with no two
end-use profiles being alike. Some end uses, such as heating, cooling, ventilation, and lighting,
were found, to some degree, in all types of buildings. However, other end uses reflected the
special activities performed within particular types of buildings.
Space-Conditioning Intensities
Space conditioning--heating, cooling, and ventilation--accounted for 45 percent of all energy
consumed in commercial buildings in 1989. Natural gas was the dominant energy source for
space heating in commercial buildings in 1989, providing 63 percent of all the energy consumed
for space heating.
-
Whether electricity is measured by site energy (consumed by the end user) or by primary energy
(consumed at the generating plant), natural gas provided a much higher percentage of the space
heating energy consumed in buildings constructed during the 1980's than electricity did, even
though the amount of floorspace heated by the two energy sources was roughly equal.
- Buildings constructed in the 1970's had the highest cooling intensities, defined as the ratio
of energy used for cooling to the product of the cooled square footage, the annual building
operating hours, and the average daily cooling degree-days (CDD's).
- Larger buildings had the highest ventilation intensities, defined as the ratio of energy used
for ventilation to the product of the square footage and the annual building operating
hours.
Intensities of Other End Uses
Other end uses--lighting, water heating, cooking, refrigeration, office equipment, and
miscellaneous uses--accounted for 55 percent of all energy consumed in commercial buildings in
1989. Lighting intensities were defined as the ratio of energy used for lighting to the product of
the lighted square footage and the annual building operating hours. Intensities for the remaining
end uses were defined as the ratio between the energy used and the product of square footage
and the annual operating hours.
-
Office buildings had the highest intensities for lighting and for office equipment.
Buildings constructed during the 1970's and 1980's had the highest lighting intensities,
while the oldest buildings had the lowest lighting intensities.
- Food service and health care buildings had the highest water-heating intensities per square
foot--more than five times the average for all buildings.
- Food sales and food service buildings had the highest energy intensities for cooking and
refrigeration.
Targets for Reducing Energy Intensities
The method used to determine targets for reducing energy intensities was to extrapolate the
energy consumption patterns of the 1980's buildings to the entire commercial building stock.
Intensities were based upon the entire building stock, not just buildings using a particular fuel
for a given end use. This method of extrapolation reflected both the level of penetration and the
efficiencies of 1980's technologies in computing hypothetical consumption levels for the total
building stock.
-
If all commercial buildings used natural gas for heating with the same intensity as did buildings
constructed in the 1980's, the total consumption of natural gas for space heating would fall 201
trillion Btu, or 17 percent.
- If all buildings used electricity for cooling with the same intensity as did buildings
constructed in the 1980's, the total consumption of electricity for cooling would drop by 9
percent (23 trillion Btu). However, the consumption of electricity for ventilation would rise by 5
percent (14 trillion Btu), for a net reduction of 9 trillion Btu, or 2 percent.
The analysis showed that lighting and office equipment presented especially worthwhile
opportunities for moderating future growth in energy demand by increasing energy efficiency.
Although energy efficiencies may have improved during the 1980's, the demand for these two
energy services, especially for office equipment, also increased dramatically.
-
If all commercial buildings had the same lighting intensity as buildings constructed in the
1980's, consumption of electricity for lighting would increase 9 percent (94 trillion Btu).
- If all buildings used energy for office equipment with the same intensity as 1980's
buildings, consumption of electricity for office equipment would increase by 26 percent (99
trillion Btu).
View and/or Print Full Report
File Last Modified: April 7, 1997
- Contact:
- alan.swenson@eia.doe.gov
- Alan Swenson
- End-Use Analyst
- Phone: (202) 586-1129
- Fax: (202) 586-0018
- Contact:
- Joelle Michaels
- joelle.michaels@eia.doe.gov
- CBECS Manager
- Phone: (202) 586-8952
- FAX: (202) 586-0018
URL: http://www.eia.doe.gov/emeu/cbecs/cbecs2e.html
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