At a time when the oil and gas industry claims that methane emissions from their well sites are coming down, here’s a study that adds scientific weight to the argument that emissions may actually be HIGHER than they claim.
A new study by researchers at the Cockrell School of Engineering at the University of Texas at Austin, published today in Environmental Science and Technology, took a look at two key processes in oil and gas production – pneumatic controllers and liquids unloading – and concluded that average methane emissions from pneumatic controllers are 17 percent higher than the estimates industry has been citing, and total emissions from these devices may be more than twice as high as they’ve been saying. According to the UT study, together, pneumatic controllers and liquids unloadings account for 40 percent of total methane emissions from oil and gas production.
Methane is a powerful greenhouse gas, over 80 times more potent than carbon dioxide as a global warming pollutant. Unnecessary venting and leaking of methane – the key ingredient in the natural gas that we use to heat our homes, cook our food, and power many of our industries – waste a precious national energy resource. Colorado and a few other states are already taking steps to reduce this waste through sensible regulations that cover oil and gas producers, and within two weeks the federal Environmental Protection Agency will announce what it intends to do about this problem. This latest UT study is further evidence that methane leakage is a national problem and national regulation is urgently needed to reduce this powerful pollutant and set a level playing field for the over 6,000 oil and gas production companies in business in the United States today.
What Are Pneumatic Controllers and Why Are Emissions Higher?
Pneumatic controllers are devices designed to use gas pressure at the well site to open and close valves in the production process. These devices are designed to emit a certain amount of methane during normal operation. Some controllers are designed to emit a small amount of methane during normal operation, while others are designed to emit a large amount. The UT study found that 30 percent of the high-emitting controllers were operating as designed, suggesting that one way to get methane emissions from oil and gas wells under control is to require producers to replace these high-emitting controllers. The other 70 percent of high-emitting controllers were malfunctioning devices. To address this problem, Colorado, Wyoming, Pennsylvania, and Ohio all require periodic leak detection and repair at well sites, and we believe that this sensible measure should become a national requirement.
EPA estimates that these widely used pneumatic controllers are now the largest and one of the fastest-growing sources of production emissions. And the UT study confirms this. UT researchers measured 377 controllers at 161 well sites, reporting an average of two to three controllers per site, in contrast to current estimates that assume only one controller per well site.
There are more than 500,000 wells that produce oil and gas in the United States today, with at least that many pneumatic controllers installed. Depending on the number of pneumatic controllers at each well site, methane emissions from pneumatics could be more than 50 percent higher than current industry claims.
What are Liquids Unloadings and Why Do They Matter?
Beyond pneumatics, UT measured methane emissions during events at natural gas wells called “liquids unloading.” This is a common process operators use to purge liquids that accumulate during, and can inhibit, production. UT’s estimate of methane emissions from liquids unloadings are in line with current EPA estimates, confirming the activity as the third largest source of production emissions after pneumatics (No. 1) and equipment leaks (No. 2). As with pneumatics, a select subset of total liquids unloadings operations accounted for the majority of emissions from liquids unloadings UT surveyed. The way to address this problem may be through the application of “smart” automation of the unloading process and/or through some kind of annual limit on total emissions allowed from this activity.
Why Voluntary Measures Won’t Cut It.
According to the UT study, 20 percent of the pneumatic controllers and liquids unloadings events surveyed were responsible for 80 percent of the emissions reported in the study. This suggests that there is much that can be done to reduce methane emissions from oil and gas production simply by doing a better job of finding high-emitting equipment and either replacing or fixing it. But what this also suggests is that there are literally hundreds of thousands oil and gas wells out there right now that are needless spewing methane into the atmosphere, contributing to climate change, and wasting natural gas that could otherwise go to heating our homes or powering our industry. With over 6,000 oil and gas producers in business today – some large, some small, most you’ve never even heard of – it would be naïve to think that all of them will take the simple but necessary steps to reduce needless emissions at their site. The data gathered by the UT study certainly suggest that they aren’t doing it today, which is why regulation that sets basic expectations and a level competitive playing field are so important.
Some oil and gas producing states have started to take action, but now the ball is squarely in EPA’s court. We await their decision. Please let them know what you think.
Image source: Cockrell School of Engineering