Energy Analysis Methodology for Assessing Environmental Impacts

Several years of developmental research have contributed to the evolution of an energy analysis methodology to assess the environmental impacts of transportation facilities. Recent energy analysis research projects and case study applications have indicated that the methodology may offer significant improvements to the environmental analyses used to assess the impacts of transportation facilties and operations. NCHRP Project 20-11B was therefore established to develop an applications manual that succinctly describes the theories, tools, procedures, and data sources necessary for applying the energy analysis methodology. The project has succeeded in this regard and, through explicit descriptions of energy analysis procedures and identification of their range of applicability in the transportation field, the states have available to them a manual that will provide a better understanding of the methodology and facilitate its use. In the manual developed in NCHRP Project 20-11B, energy is used as the common measure. It is used in a procedure to quantitatively evaluate the effect on human-system processes of environmental impacts due to transportation actions. Comparable energy accounts are evaluated for a variety of individual impacts to the natural environment. The energy analyses follow the laws of thermodynamics to evaluate the minimal energy cost of replacing natural-environment goods and services that may be stressed by transportation actions. The severity of different kinds of environmental impacts may be compared according to those energy costs. In addition, knowing energy use/dollar correlations for a given economy, the energy costs may be translated into money costs. By having evaluated the various free work contributions from the natural environment, the analysis shows how much the individual or aggregated environmental impacts may change the total effectiveness of transportation investments. /Author/