Almost all of the climate-affecting methane leaks from the oil and gas infrastructure could be reduced at relatively little expense, often by simply tightening bolts or replacing worn seals, suggests a new study by the Boston-based Clean Air Task Force released today. (See related story: “Green Fracking? 5 Technologies for Cleaner Shale Energy.”)

The report noted that unintentional leaks account for 30 percent of the methane emitted by the oil and gas industry, which after agriculture is the second biggest source of the potent greenhouse gas. (The bulk of the emissions is intentionally vented into the atmosphere, to regulate the extraction, processing and transmission of the fuels.)

Energy companies could recoup the cost of plugging 90 percent of those leaks in as little as a year’s time, by selling natural gas that otherwise would have escaped into the atmosphere, according to the report.  (The U.S. Environmental Protection Agency has estimated that the typical natural gas processing plant loses natural gas emissions worth about $230,000 each year.)

But beyond immediate repairs, an ongoing effort to monitor and actively curb methane would end up costing the companies money, because they would have to conduct monthly or quarterly inspections of well sites, using infrared cameras to scrutinize equipment for methane missions.  As a result, most oil and gas facilities would end up spending slightly more than they saved, with companies shelling out as much as $2,500 per well and up to $8,000 per gas plant annually.

Even so, the cost of doing such inspections would amount to a tiny fraction of the revenue that natural gas producing companies generate, said David McCabe, an atmospheric scientist for the task force.  In Colorado, which in February became the first state to require methane inspections new regulations , McCabe said that the tests will cost about $18 million annually—three-tenths of a percent of the $6 billion in income generated by natural gas in the state.

“Regularly inspecting oil and gas facilities is an inexpensive and logical way to reduce methane emissions,” McCabe said.

The study is based on data gathered by inspectors who used infrared cameras to scrutinize 4,000 well sites, gas compressor stations and processing plants, about 90 percent of them in Canada with the remainder located in the U.S.  The inspectors found more than 58,400 individual pieces of equipment—an average of 13.6 per facility—that were emitting methane. Nearly 40,000 of those pieces of equipment had unintentional leaks, most of which could be fixed with simple repairs. The median cost of the fixes was just $50.

Although there’s widespread concern about the environmental risks of fracking, the study found that most of the total methane emissions actually come from plants and compressor stations rather than wells. And only 17 percent of the emissions from well sites are accidental leaks, with the rest being vented intentionally.  (See related, “Methane Emissions Far Worse Than U.S. Estimates.“)

While detecting and fixing leaks would make a significant dent in methane emissions, curbing intentional venting clearly would have much more dramatic impact.  According to Ben Ratner, an policy expert in methane control for the Environmental Defense Fund, that would require upgrading equipment. The conventional pumps used to inject fracking chemicals into wells, for example, utilize the pressure of natural gas in the well as a power source, and vent it to regulate themselves.  Switching to another power source, such as solar-generated electricity, would eliminate nearly 6 billion cubic feet of methane emissions annually.

EDF recently released its own report analyzing potential opportunities for reducing methane emissions in the oil and gas industry, emissions that EDF estimates will amount to 404 billion cubic feet for onshore production in 2018.

Ratner said that while many companies are voluntarily moving to curb their methane output, stricter government regulation akin to Colorado’s new rules was needed. “The good news is that some companies are leading the way, but we need strong policy to level the playing field. We have thousands of gas producers, which means that we need protective rules that are strongly enforced.” (See related, “Air Pollution From Fracked Wells Will Be Regulated Under New U.S. Rules.”)