The US Department of Energy and EPA’s Inspector General have called attention in the past two weeks to an important issue – harmful methane emissions from the systems that distribute natural gas in cities and towns. There’s been some effort to clean up methane from natural gas systems in recent years. For example, EPA’s 2012 rules covering hydraulically fractured gas wells and some new equipment will reduce methane from some specific sources as a “co-benefit” (the rules target other pollutants in gas, not methane). Some states, including Colorado, have also issued important rules. However, these rules have focused on production of oil and gas (EPA’s rules have a few measures that regulate pollutants from gas processing plants, too). Unfortunately, EPA and the states have neglected cleanup of local gas distribution systems, as the IG’s report makes clear. This is an important issue, and both DOE and the EPA IG have proposed useful, and important, ideas to speed up replacement of leaky, unreliable, outdated, and sometimes hazardous distribution pipelines made of cast iron or unprotected steel.
But both the Inspector General’s report and the DOE initiative miss one of the most important opportunities to reduce emissions from gas distribution: cleaning up methane leaks from aboveground equipment in the distribution systems, like city gates and stations where gas is metered and regulated.
EPA’s inventory of methane emissions shows that methane emissions from these large stations are actually somewhat larger than emissions from outdated underground pipes. And these emissions can be cleaned up quickly and cheaply. Our research has shown that leaks at wellpads and gas compressors can be cheaply found and fixed, potentially eliminating millions of tons of emissions at low cost, despite the fact that these facilities are often dispersed in remote locations. EPA analysis of industry reports on leak surveys (see Appendix C of this report on GHG cleanup costs) has shown that emissions at large distribution facilities are also cheap to clean up.
The climate damage in the twenty years after emissions caused by methane leaks from US gas distribution systems is greater than the carbon emissions from power plants* from any one state, except Texas, and cleaning up this methane is a critical complement to cleaning up CO2 from power plants – the most important priority for climate stabilization. While voluntary programs like Natural Gas Star have helped reduce upstream methane emissions, they have only reduced distribution emissions by 3.4%. Modernizing old, unsafe, leaky pipelines and distribution infrastructure is a key priority that will make these systems safer and more reliable and could create hundreds of thousands of jobs.
Replacing leaky distribution pipelines is urgently needed, and it is good that the EPA Inspector General and DOE have brought some new thinking to this infrastructure challenge. Fixing methane leaks at aboveground distribution stations needs attention too – these leaks are a large source of pollution, and they are cheap and simple to fix.
EPA needs to use its authority under the Clean Air Act to regulate methane directly and require gas utilities to find and fix leaks at these facilities. Neither the pipelines in our cities nor the unnecessary leaks from equipment aboveground should continue to be neglected.
* As mentioned, we are using a 20-year global warming potential to compare the climate damage from methane and CO2 here. Its more typical to use a 100-year GWP – for example, EPA always uses the 100-yr GWP in their analyses. It’s critical to consider both metrics. Methane, pound for pound, traps much more heat than CO2, but methane only lasts about a decade in the atmosphere, while CO2 lingers in the climate system for centuries. That’s part of why cleaning up CO2 is the highest climate priority. Methane reductions, on the other hand, are very important as we try to reduce the rate of warming in the coming decades.