Propulsion and power rapid response research and development (R&D) support - Delivery order 0011: Advanced propulsion fuels research and development -- Subtask: Framework and guidance for estimating greenhouse gas footprints of aviation fuels

Although there have been extensive analyses of the greenhouse gas emissions associated with petroleum based fuels and alternative fuels, there are still substantial uncertainties associated with some of the estimates of the greenhouse gas impacts of these fuel systems. Nevertheless, a variety of governmental agencies and non-governmental organizations are developing approaches for estimating or regulating the emissions of greenhouse gases associated with the production and use of transportation fuels. Specifically Congress included Section 526 in the EISA of 20071 that states: No Federal agency shall enter into a contract for procurement of an alternative or synthetic fuel, including a fuel produced from nonconventional petroleum sources, for any mobility-related use, other than for research or testing, unless the contract specifies that the lifecycle greenhouse gas emissions associated with the production and combustion of the fuel supplied under the contract must, on an ongoing basis, be less than or equal to such emissions from the equivalent conventional fuel produced from conventional petroleum sources. In addition, a number of states are considering greenhouse gas emission regulations. For example, the California Global Warming Solutions Act of 20062 has resulted in draft regulations that establish a limit for life cycle greenhouse gas emissions of transportation fuels. Both the California low carbon fuel standard and Section 526 of EISA require a life-cycle evaluation of the greenhouse gas emissions of transportation fuels, and this is becoming a common approach to considering greenhouse gas emissions. Employing a life cycle approach in estimating greenhouse gas emissions from the production and use of transportation fuels means assessing all emissions from field to the vehicle tank and from tank to vehicle exhaust. This scope of emissions assessment is frequently referred to as a "well-to-wheels", or in the case of aviation, a "well-to-wake" analysis. With the significant interest in both the Department of Defense (DOD) and the civil aviation community to purchase only alternative fuels that are in compliance with emerging greenhouse gas emission requirements, a consistent framework for conducting a LCA of greenhouse gas emissions must be developed to assure that candidate fuels are adequately evaluated for environmental compliance.