Among greenhouse gases, methane should be particularly amenable to deliberate cuts in emissions. Recognition that this is would profitably inform US Environmental Protection Agency as it considers regulating methane releases from oil and gas operations.
Methane's dual role as an agent of and antidote to global warming deserves similar attention. As the lightest hydrocarbon, the gas emits less carbon dioxide when burned to produce a unit of heat energy than its heavier brethren do. Indeed, much of a recent reduction in US emissions of CO2 relates to displacement by natural gas of coal in the generation of electrical power. But methane, while accounting for far less of total human emissions of greenhouse gases than CO2, is more than 20 times as potent as the more dominant gas as a warming influence in the atmosphere over 100 years. In the battle against warming, a promising strategy is to burn more methane in place of heavier hydrocarbons and to leak less.
Progress evident
Progress on this front is evident. Industry groups, anticipating EPA's decision, legitimately want everyone to know about it. To cite just one of several sets of numbers published recently, America's Natural Gas Alliance says the natural gas industry has lowered methane emissions by 17% since 1990 while increasing gas production by 37%. In that period, according to ANGA, methane emissions have fallen by 25% from production, by 12% from transmission, and by 22% from distribution.
Improvement results from a combination of industry and governmental programs and a compelling truth that makes lowering emissions of methane especially alluring: What leaks can't be sold. On their own and in partnership with regulators, through programs such as EPA's 21-year-old Natural Gas STAR Program, companies have trimmed methane emissions with improvements to equipment and practices, including green-completion technologies. Also lowering methane leaks, as a side benefit, is a regulation EPA imposed in 2012 targeting emissions from oil and gas wells of volatile organic compounds to combat ozone formation.
Experience with industry-government cooperation should combine with impressive, measurable progress in emission reduction to provide a solid base for the decision EPA will make, possibly by month's end, whether and how to regulate methane from industry operations. Further help comes in a new study from the University of Texas at Austin showing the origins of most wellsite emissions of methane. Leading the research was David Allen, a chemical engineering professor who chairs EPA's Science Advisory Board. Participants in the study included Allen's research team, the Environmental Defense Fund, an independent scientific advisory panel, and 10 oil and gas companies.
A Dec. 9 report from this impressively ecumenical project covers the second study phase, which concentrated on two major sources of wellsite methane emissions spotlighted in the first phase: pneumatic (gas-actuated) valve controls and liquid unloadings. Importantly, the study found that relatively small shares of wells with pneumatic devices and of those subject to unloading account for, by far, most emissions from these sources.
Worst fear
If heeded by EPA, this insight can address the industry's worst fear in this issue: the possible adoption of broad, national controls on methane emissions from oil and gas equipment. A measure like that would add costs to all industry work related to natural gas yet improve emission performance in a conspicuously small part of it. The wall-to-wall approach, moreover, might keep real improvement from finding its way into the tight corners that really need it.
EPA will hear, of course, from groups demanding the strictest possible regulation of methane. It shouldn't be swayed. It should want to know as much as possible about emission sources-then rely to the extent possible on voluntary remediation. That approach is working. Whatever regulation it does apply should be carefully targeted and light-handed. Recent history offers little hope for such restraint. The demonstrated success of voluntarism and collaboration in the mitigation of oil-field releases of methane, however, should make eager regulators want, first, to do no harm.