March 21, 1996
EIA Session Summary
"To achieve efficiency in energy use" is
part of the U.S. Department of Energy's mission. By measuring energy-efficiency changes,
we have a way of knowing if we have achieved our goals.
Energy efficiency is an interesting and useful
concept for analyzing energy use. Energy efficiency is usually analyzed in relative terms;
For example, "is energy efficiency increasing or decreasing," rather than
"what is the energy efficiency of a particular energy-requiring product or
service?" Considered in relative terms, energy efficiency is a fairly simple concept
to describe theoretically--energy-efficiency improvement occurs when more or enhanced
goods or services are provided with level energy inputs. Energy-efficiency loss occurs
when more energy inputs are required to produce the same or reduced products or services.
In reality, however, energy efficiency is difficult
to measure. Because energy needs to be assessed relative to the amount of product or
service provided, energy-use rates, commonly called energy intensities, are the measures
ordinarily used to assess efficiency trends. Energy intensities reflect not only energy
efficiency but also changes in other effects such as weather and extent of occupancy.
However, the advantage of considering individual energy intensities is that you may easily
measure and track them over time.
Energy efficiency is particularly difficult to
measure in the transportation sector. Participants in the workshop pointed out that EIA
collects very little transportation data. Therefore it has the least experience using
transportation data and very little control over the quality of the data from outside
sources.. EIA's transportation data covers only the residential sector. EIA's Residential
Transportation Energy Consumption Survey (RTECS) cannot be the only source of data used
for efficiency analysis in the transportation sector. EIA budget limitations also call for
a cancellation of the RTECS. Therefore these data may not be available for future use.
How Should Energy Efficiency be Defined
Workshop participants suggested that the concept of
"efficiency" must be put in its proper place; it is entirely value-driven. Value
implications depend on who the customer is. Value judgements are inherent in every
measurement decision, because one must define what measures what concept.
Among other participant comments were:
- EIA Needs to Obtain Basic Definitions. Because
the transportation sector is so diverse, there must be some consensus building prior to
developing efficiency indices. Basic definitions for issues such as the national goal,
activity measures, and equity need to be clarified and agreed upon.
- Definition Should Consider Energy Costs. No
one has suggested using energy cost rather that Btu, because cost is not an issue because
gasoline is cheap. Yet fuel prices are important especially with regard to efficiency.
What Are the Appropriate Energy-Efficiency Indicators
Analysis of the Transportation Sector?
Data limitations severely restricts the
development of energy-efficiency demand indicators for the transportation sector.
Nevertheless, some participants thought that EIA's report does a good job measuring the
transportation service provided. Participants argued, though, that not all vehicle-miles
traveled (VMT) or passenger miles (PMT) are equal, e.g., air package versus oil pipeline
or riding a Lexus versus a Geo Metro. The severe data limitations will not allow you to
get beyond PMT and VMT. EIA must explain to the reader the limitations of Btu/PMT or
Btu/VMT. Data limitations force the use of intensity indicators rather than
Who Is the Audience for Transportation
Sector Efficiency Analysis?
The audience for this type of analysis is quite
diverse. The participants suggested the following as potential users of energy-efficiency
- Policy Analysts with National Concerns. Participants
were asked to rank users of energy-efficiency analysis. The first priority was the policy
analysts; energy efficiency is affected by changes in standards and regulations. Criteria
pollutants are needed by the U.S. Environmental Protection Agency (EPA) and oil use and
efficiency data are vital for security concerns.
- Policy Analysts with International Concerns.
Measures are useful to show the interaction of energy use and the environment, and
determine if we are meeting not only national goals but international ones as well.
Efficiency and greenhouse gas data are required by the international community. The
clients are countries that are signatories to various international conventions and
members of International Energy Agency (IEA). There must be an agreement on how to account
for CO2 and measure efficiency.
- Congressional Staff. Energy-efficiency
analysis could assist congressional staff in preparing energy-related legislation.
- Government Program Office. Government program
offices such as DOE's Office of Transportation Technologies' Research and Development
Program office could track data over time to see if policies reduced energy usage.
- Modelers. Modelers could use an
energy-efficiency data series to predict the future. EIA's National Energy Modeling System
(NEMS) focuses on growth rates; EIA's efficiency analysis could provide reality checks.
What Are the Significant Structural Difficulties and
Other Important Analytical Issues in the Transportation Sector?
The transportation sector presents
unique difficulties when undertaking efficiency analysis. Workshop participants thought
that some of the major areas of difficulty and other important issues were:
- Accounting for Quality of Service Differences.
A complicated structural problem in the transportation sector analysis of energy
efficiency is attempting to incorporate differences in the quality of service in personal
- Available Data are Inadequate. EIA cannot
begin to define the quality of service, especially in freight, for which the ton-mile data
are only inter-city. The Commodity Flow Survey by the Bureau of Transportation Statistics
may help even though it is not complete. There is very poor information on ton mileage
except for railroads. EIA should be very careful to remind people where data are weak,
e.g., freight carried in the belly of a passenger aircraft. What can be measured includes
vehicle weight, horsepower, test mpg (reported by EPA) and passenger volume. However, this
ignores how the truck is used, i.e., full capacity, empty backhaul. Yet this begs the
question: are the data good enough to even justify the analysis?
- Circuitry Issues Need to Be Addressed. Although
the shortest (and most efficient) way to get from point A to point B is by traveling a
straight line, the phenomenon of the hub system has affected passenger travel,
transportation modes, and energy use. Circuitry should be addressed in terms of behavior
(longer routes chosen to increase frequent flier miles), economics (profitable routes and
tax incentives), and technology (size of planes and energy efficiency of mass transit).
- Accounting for Embedded Energy. If we include
energy embedded in the construction of mass transit, then we would also need to include
the energy consumed for auto manufacturing. This is the same phenomenon as the use of
compressed gas versus gasoline vehicles without taking into account the energy used to
compress the gas. It seems that it depends on the usage of the energy-efficiency indicator
as to whether embedded energy should be included or not. For greenhouse gas emissions,
embedded energy should be included.
- EIA Needs to Disaggregate Efficiency Analysis. The
data must be disaggregated; composite measures are not useful for program analysis or
research and development (R&D) planning. Freight and personal travel must be
separated. Composites may be useful to Congress.
- Need Detailed Indices. For modeling, indices
may have to be more detailed over time because they need to demonstrate causes of events;
it is important for us to be able to perform intermodal comparisons, such as mass transit
versus passenger car. Passenger-Miles-Traveled (PMT) and Vehicle-Miles-Traveled (VMT)
provide different major trends data. For example, states rely on VMT for state revenue
information and PMT is used for mass transit policy-making. The availability of both types
of data are important.
- Demographic Data Should be Used. Demographics
would be interesting for indicator analysis but are likely unaffordable.
What is the Appropriate Role for EIA in Analysis
Energy Efficiency in the Transportation Sector?
Measuring Energy Efficiency in the United States'
Economy: A Beginning is EIA's first venture into providing this kind of information for
the transportation sector. One of the workshop participants noted that at least EIA was
honest about how little we know. The report illustrated the weaknesses in the
transportation data. Other participants suggested roles for EIA such as:
- A Credible Source of Information. EIA is an
independent agency and as such it has the advantage of being credible and objective.
- EIA Takes a Leadership Role and Attempts to
Provide More Consistent Transportation Data. Analysis in which energy intensities are
based on PMT or Ton-Miles-Traveled may be impeded by the diverse sources of data and the
problem of incongruity between these sources. EIA could take a leadership role in the
reconciliation of diverse data series for the transportation sector, calling for EIA to
provide linkages and the necessary conversion factors so that existing data would provide
more consistent coverage of the entire sector.
- Filling in Data Gaps. EIA could provide better
coverage of energy consumption in the transportation sector by filling some of the largest
gaps by asking more detailed questions of the energy suppliers about their customers'
end-uses. EIA does not even have a good series of new vehicle efficiencies beyond EPA's
test mpg. There is no readily available information on efficiencies for railroad
locomotives and for several aircraft types. This is an example of the kind of technical
work EIA can do that will offer great value to users since changes in transportation
efficiencies influence behavior and stock turnover.
- Integrating its Reports to Obtain a More
Comprehensive Picture of Energy Efficiency. The EIA annual report on greenhouse gases
should be integrated with the alternative fuel report and energy-efficiency indicators
- A Conduit for Efficiency Research by Other
Researchers. EIA could conduct literature searches and provide summary analysis of
other efficiency analysis to the extent possible.
- Maintaining, as First Priority, EIA's Main Role as
Data Collector. With the reality of budget shrinkage, EIA's main role is the
collection and publication of data. This needs to be emphasized.
questions on this topic may be directed to:
Modified: October 17, 1999