||From a life cycle perspective, baseload power is NETL's preferred basis for comparing energy sources. For fossil energy systems, the emissions from power plants account for the majority of greenhouse gas (GHG) emissions. However, focusing on the activities that precede the power plant is still necessary in order to identify near-term opportunities for GHG emission reductions. NETL's upstream natural gas model allows detailed modeling of the extraction, processing, and pipeline transmission of natural gas. This model can identify key contributors to the GHG emissions from the natural gas supply chain, and has parameters that can be used to assess opportunities for reducing GHG emissions. The model shows that current domestic natural gas extraction, processing, and pipeline technologies leak 1.2% of the methane that is extracted at the wellhead. Improved practices, such as those in the latest New Source Performance Standards (NSPS), can reduce this upstream methane leakage rate. From a life cycle perspective (1 MWh of delivered electricity), power production from natural gas has lower GHG emissions than power produced from coal. There are several methods and technology combinations that can be used for determining how high the upstream natural gas methane leakage rate has to be in order for the life cycle GHG emissions from natural gas power to equal those from coal power. Ongoing research is developing data that will improve the accuracy of NETL's upstream natural gas model.