# Full-Fuel-Cycle Accounting

Given concerns about the environmental impacts of fossil fuel use, there is a keen interest in developing a broad range of new energy sources and technologies. This interest creates a need for metrics that can reliably quantify the costs, benefits, and potential trade-offs of different alternatives. The EES group developed a definition of a full-fuel-cycle (FFC) metric that is flexible enough to describe a wide variety of energy production chains and has sufficient mathematical rigor to allow meaningful comparisons between them. The term FFC refers to the complete fuel production chain including extraction, processing, conveyance to the retail distribution center, and delivery to final consumers. For ease of use in applications, the metric is defined as an FFC multiplier which, when applied to the point-of-use energy consumption, gives an estimate of the FFC energy use. We also show that the FFC multiplier can be used to provide precise and intuitively reasonable definitions of other energy production metrics such as EROI (energy return on energy invested). The multiplier is a non-linear function of a set of energy–intensity parameters that depend only on directly observable physical data.

To conduct an FFC analysis, the EES group can use the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model or NEMS. NEMS is a public domain, multi-sectored, partial equilibrium model of the U.S. energy sector. Each year, DOE/EIA uses NEMS to produce an energy forecast for the United States, the *Annual Energy Outlook (AEO)*.