Assessing Inter-City Passenger and Inter- and Intra-City Freight Transport Energy and GHG Intensities

Focus Area



Air Quality







Research Idea Scope

Problem Statement
Energy intensity values (energy use per unit of activity) are basic data for forecasting, policy analysis, planning, and monitoring progress toward energy and environmental goals. They are essential for predicting the impact of changes in the structure of passenger and freight transportation over time and in response to technology advances and policy initiatives. Because greenhouse gas emissions are closely linked to energy consumption, energy intensities are also key variables in modeling climate change impacts of transportation activities. In general, however, only the most aggregate energy intensity values are readily available (e.g., energy use per total revenue passenger-mile for air travel, energy use per vehicle-mile for automobile travel, etc.), and for some modes (e.g., truck freight) even the most basic estimates of energy use per unit of activity are not available. Greenhouse gas (GHG) intensity values are similarly lacking.
The lack of detailed, comprehensive, consistent, and objective measures of modal energy and GHG intensities handicaps a range of analyses. In many cases, analyses must rely on generic estimates based on total activity and fuel use developed by or for agencies like DOT’s Federal Highway Administration (FHWA), EPA’s MOVES model, and DOE’s Energy Information Administration (EIA). The most recent comprehensive study of passenger and freight energy intensities is now more than 30 years old.
Developing a consistent set of comprehensive and objective energy and GHG intensity estimates will require a substantial research effort. This research should survey all modes, but the primary focus should be on Inter-City Passenger and Inter- and Intra-City Freight Transport Energy and GHG Intensities. The research should make distinctions, where possible of different spatial scales (e.g., national, regional, metropolitan). The level of detail should reflect analytical needs as well as the availability of reliable and accurate data. Detail is important to ensure valid comparisons across modes and functions and to improve the accuracy of derived estimates, such as greenhouse gas emissions. Specific tasks will include:
·      Reviewing United States and international literature, both to obtain modal energy intensity estimates for comparative purposes and to identify data sources and methods.
·      Surveying the literature and relevant agencies to identify and evaluate the most important uses of energy intensity numbers
·      The data are scattered and representative driving cycles do not exist, so the effort should cover these gaps.
·      Determining modal, functional, and spatial structure of intensity estimates to be derived based on the availability of data, the identified needs/uses for energy intensity estimates, and relevant parameters.
·      Selecting methods and data sources for developing the estimates and implementing them in a computer model (e.g., a spreadsheet) so that estimates can be made for both the past and future, according to the availability of data.
Related Work
Rose, A.B., 1979. Energy Intensity and Related Parameters of Selected Transportation Modes: Passenger Movements, Oak Ridge National Laboratory Report ORNL-5506, Jan.
Rose, A.B., 1979. Energy Intensity and Related Parameters of Selected Transportation Modes: Freight Movements, Oak Ridge National Laboratory Report ORNL-5554, June.
Davis, S.C., Diegel, S. and Boundy, R.G. 2009. Transportation Energy Data Book. Edition 28. U.S. Department of Energy/ Oak Ridge National Laboratory. ORNL-6984. Oak Ridge, TN.
Urgency/PriorityThe proposed research will contribute to the ongoing dialogue on climate change strategies, policies, and investments by providing a consistent, objective basis for comparing alternative technology and policy options.

Urgency and Payoff

The desired project outcome is a final report and a computer model, together with instructions for its operation, to be used by a range of federal, state and local agencies, operating authorities and user groups.
If successful, this research will refine our understanding of the relationship between energy intensity and various technical and operational parameters and provide an enhanced capability to compare alternative technological and policy options.

Suggested By

RNS. Sponsoring Committee: A0020T, Special Task Force on Climate Change and Energy Source Info: Special Task Force on Climate Change and Energy January 2010 Workshop