Establishing Standard Source Energy and Emission Factors for Energy Use in Buildings

Energy use in buildings is most commonly analyzed by using the energy measured at the site. Some analysts also calculate the source energy and emissions from the site energy. Source energy use and emission profiles offer better indicators of the environmental impact of buildings and allow other metrics for comparison of performance. However, there are no standard factors for calculating the source energy and emissions from the site energy. The energy and emission factors used are derived from different data using different methods resulting in wide variations, which makes comparisons difficult. In addition, these factors do not include the full life cycle of the fuels and energies, but only the combustion and transmission portions of the life cycle. The recently available U.S. Life Cycle Inventory (LCI) Database provides LCI data for energy, transportation, and common materials. The LCI data for fuels include all the energy and emissions associated with the extraction, transportation, and processing of the fuels. This paper describes how the LCI data, along with other emissions data and energy consumption data from the Energy Information Administration, were used to generate source energy and emission factors specifically for energy use in buildings. The factors are provided on national, interconnect, and state levels. This effort was part of the U.S. Department of Energy Performance Metrics Project, which worked to establish standard procedures and performance metrics for energy performance of buildings.