Reducing Greenhouse Gas Emissions with Natural Gas (May 2011)
The U. S. Environmental Protection Agency recently released their annual Greenhouse Gas Inventory. The new release includes a considerable increase in methane emissions resulting from the production of natural gas. The revision is primarily attributable to assumptions regarding drilling practices, particularly those related to the hydraulic fracturing of shale formations. Given the increases in the revised data, some have questioned whether natural gas can, or should, be pursued as a viable tool for reducing greenhouse gas (GHG) emissions.
The purpose of this analysis is to consider what impact, if any, the revised methane numbers have in terms of the attractiveness of natural gas in reducing GHG emissions. While AGA has not performed an independent analysis of the revisions performed by EPA, it recognizes that significant questions have arisen related to the revisions. These questions must be fully scrutinized and resolved. That, however, is not the purpose of this analysis which was performed assuming that the EPA revisions are entirely accurate.
GHG emissions remain significantly less for natural gas than for coal or oil on a Btu equivalent basis. AGA's analysis concludes that the GHG emissions advantage of natural gas is slightly greater today than in 1990 based on EPA and DOE data.
Despite the possibility of a temporary increase in one portion of the overall natural gas related GHG emission profile, there is no question that natural gas can be substituted for other energy forms with very positive GHG effects. In terms of generating electricity, for example, using natural gas as a generating fuel can cut GHG emissions in half, or more, relative to coal.
This advantage is multiplied with the efficiency advantage offered by many gas applications. Greater efficiency means that less energy must be consumed to obtain the same product (such as heat, hot water, or electricity), therefore GHG emissions are reduced.