Increased reliance on natural gas will create many opportunities, but many challenges as well. The main challenge is that expansion of the natural gas market will result in increased emissions of methane (CH4), a potent greenhouse gas. The level of increased emissions is a function of the industry maintenance practices and technologies used to produce and deliver natural gas.
While the global climate change debate has focused on carbon dioxide (CO2), the International Panel on Climate Change (IPCC) reports that CH4 emissions are more potent in terms of their global warming potential. This study examines CH4 emissions produced by the U.S. natural gas industry and how to minimize future CH4 emissions as the annual U.S. market for natural gas expands from its current 22 Tcf level to 30 Tcf by 2020. The study finds:
- Under the business-as-usual case for new applications only, CH4 emissions could rise from 35.6 million metric tons of carbon equivalent (MMTCE) in 2000 to 51.0 MMTCE in 2020. That translates into a 43.4 percent increase in CH4 emissions from a 52.8 percent growth in natural gas demand.
- But when cost-effective technological and operational improvements are implemented for new and replacement applications in a 30 Tcf gas market, CH4 emissions rise from 35.6 MMTCE in 2000 to 40.7 MMTCE in 2020. This represents a 14.4 percent rate of growth in CH4 emissions, 25 percent below the comparable business-as-usual estimate.
- The business-as-usual CH4 emissions are projected to rise by 38.8 percent in the transmission and storage sector from 2000 to 2020. But adopting currently available technologies and maintenance practices would create a net reduction in current CH4 emissions from this sector, even with a 52.8 percent increase in gas demand.
- Nevertheless, economic incentives are insufficient to compensate for the greater capital and operating costs associated with these methane-cutting technology options. In fact, the Natural Gas STAR Program notes that the industry is not pursuing cost-effective options with less than a two-year payback because of competing demands for capital and even higher returns on investment. Until an early-action crediting program is instituted, such CH4 reduction investments may continue to be deferred.
