Over the years, ConocoPhillips -- an energy company so rich that it earns as much in a year as Croatia -- has positioned itself as a good guy among its peers when it comes to greenhouse gas pollution.

It is a member of a U.N.-led initiative to reduce emissions of methane, a potent greenhouse gas that is the primary component of natural gas. In the United States, it is a longtime participator in U.S. EPA's voluntary program to curb methane leaks. In January, Ryan Lance, CEO of ConocoPhillips, said in Washington, D.C., that the industry is working diligently to tackle the problem.

"Industry is working pretty hard to make sure that we do the right things and we attack methane emissions," he said.

Production and emissions

But, it would appear, ConocoPhillips' rhetoric does not always match its actions.

The company ran one of the top 10 leakiest operations among its peers in 2013, the latest year for which data are available, according to an analysis of federal and corporate data by ClimateWire (see table). Its total assets also are greater than those of the top nine other leakiest companies combined.

Leakiness ("leak rate") is defined as the amount of methane a company emits per unit of oil and gas it produces at all the oil and gas fields it operates in the United States.

Simply put, it is a measure of how methane-dirty a company is compared to its peers. ClimateWire did a similar analysis in 2012 using the best data available at the time (ClimateWire, Oct. 6, 2014).

No greenhouse gas has landed the oil and gas industry as much in the crosshairs of the federal government as methane. The gas has a global warming potential 86 times that of carbon dioxide on a 20-year time scale. Where CO2 takes centuries to millennia to warm the planet, methane is its cousin on steroids, working quickly over decades before decaying into less virulent gases. Both gases matter for the climate.


Top 10 methane polluters in the United States in 2013: Company Total assets in 2013 Unit Corp. $4.0 billion ConocoPhillips $118.1 billion Sandridge Energy Inc. $7.7 billion Cimarex Energy Co. $7.3 billion BreitBurn Energy Partners LP $4.2 billion EOG Resources Inc. $30.6 billion QEP Resources Inc. $9.4 billion Linn Energy LLC $16.5 billion Energen Corp. $6.6 billion Exxon Mobil Corp. $346.8 billion

Methane leaks are also anathema to Americans who pride themselves as efficient managers of natural resources, said Jon Goldstein, senior policy manager at the nonprofit Environmental Defense Fund (EDF). The venting, burning or leaking of natural gas is a waste of resources for state coffers, he said.

Methane leaks wasted $360 million worth of natural gas in 2013, Goldstein said, quoting from an EDF analysis.

"That is a lot of money that is not being put to good use, and not being used to invest in infrastructure and schools and health care and things like that," he said.

Conoco: 'We have made progress'

The oil and gas industry is the second-largest industrial emitter of methane in the United States, EPA data show. The Obama administration has said that by 2025, the oil and gas industry will have to cut leaks 40 to 45 percent below 2012 levels.

How the analysis was done Only the top 40 American companies that owned the most assets in 2013 were analyzed, under the assumption that the largest companies can best afford to clean up their emissions. Data sources: The Oil and Gas Journal's compilation of U.S. Securities and Exchange Commission data for the top 150 oil and gas producers in the United States in 2013. Emissions data downloaded from U.S. EPA's Greenhouse Gas Reporting Program's Envirofacts database. Methane emissions from both onshore and offshore operations were included. The emissions were broken down by component. Operated production data from the U.S. Energy Information Administration's Form 23, obtained through a Freedom of Information Act request. Oil and natural gas were added up using the conversion factor: 1 barrel of oil equals 6,000 cubic feet of gas. To gauge the efficiency of a company's operation, total U.S. emissions (onshore and offshore) in 2013 for each company were added up. That number was divided by the total oil and gas produced by the company at all the fields it operates, called "operated production." The companies were ranked by their emissions-production ratio, or "leak rate." The methodology was cross-checked with energy industry representatives and independent experts who have analyzed Greenhouse Gas Reporting Program data. -- Gayathri Vaidyanathan

The tussle now is over how this target will be met. EPA will release a draft plan this summer, but in the meantime, industry has been lobbying hard to avoid new regulations. Energy companies say they can police themselves, without a federal watchdog.

But this appears unlikely, considering the extent of leaks.

Between 2012 and 2013, ConocoPhillips' leak rate increased by 12 percent, according to ClimateWire's analysis.

The leaks coincided with a profitable year for ConocoPhillips, which earned $9.2 billion in profits in 2013. It was the third-biggest American energy company by assets, according to the Oil and Gas Journal's 2014 Survey of Top 150 U.S. Oil & Gas Companies.

A ConocoPhillips spokeswoman told ClimateWire the company has taken proactive steps to reduce its methane emissions since 2013.

"We have made progress on reducing our emissions," she said in an email. "It is a continuous process, and we will continue to assess ways and implement programs that will continue to drive reductions and allow us to operate more safely, efficiently and responsibly."

'Leakiest' N.M. basin drives emissions

The top emitter in 2013 was Unit Corp., which leaked at almost the same rate as ConocoPhillips. The world's largest publicly listed oil and gas company, Exxon Mobil Corp., was the 10th major polluter in the United States.

ClimateWire ranked only the top 40 U.S. oil and gas companies by assets, which together contributed 67 percent of the methane emissions from the production sector.

Thousands of smaller companies contributed the rest of the emissions, and many of these are likely more inefficient than the top companies. However, the analysis was restricted to the top 40 in the belief that the most profitable companies can best afford to clean up their operations.

The company that was the leakiest in 2012, Bill Barrett Corp., did not feature in the 2013 rankings. That is because Bill Barrett's profits fell and it was no longer among the top 40 energy companies.

ConocoPhillips' emissions are high because of its large presence in the San Juan Basin. This basin is located mostly in New Mexico and has the distinction of being the leakiest methane field in the United States.

Satellite photos taken by NASA show a methane plume roughly the size of Delaware hovering over northern New Mexico.

Why New Mexico's fields are so leaky is unclear and is being studied by NASA and the National Oceanic and Atmospheric Administration.

Some outliers ConocoPhillips in the San Juan basin (New Mexico) emitted 5.8 million metric tons of carbon dioxide equivalent (mtCO2e) of methane in 2013, equal to the carbon releases from 4.5 million cars. Chesapeake Energy's Anadarko Basin facilities (Oklahoma and Texas) emitted 1.3 million mtCO2e, equal to a million cars. Exxon Mobil's East Texas operations emissions equaled that of 631,586 cars. Southwestern Energy in the Arkoma Basin (Oklahoma) emitted 328,076 mtCO2e from well venting, the second-largest amount from this source. The ConocoPhillips San Juan operation was the largest. Devon Energy in the Permian Basin of Texas emitted 106,692 mtCO2e of methane from storage tanks, the largest amount from this source. Natural gas co-produced with oil can be vented or flared. The largest emissions from this source were from North Dakota and Montana's Williston Basin, followed by Texas' Permian Basin. Norway-based Statoil's operation emitted 322,978 mtCO2e, while Colorado-based QEP Energy emitted 94,917 mtCO2e in the Williston Basin. -- Gayathri Vaidyanathan

Most of ConocoPhillips' emissions in the San Juan Basin are from venting of methane to the atmosphere during a well cleaning process called "liquids unloading." The company also has abnormally high emissions from other processes and technologies.

A 2014 improvement?

Methane emissions can be curbed using "reduced emissions completions," low bleed controllers, plunger lifts and other technologies. But companies do not uniformly adopt these measures.

ConocoPhillips was relatively lax in adopting such technologies in 2013, according to its 2013 filing with CDP, a London-headquartered nonprofit that collects survey responses from major companies for investors worried about climate change.

The company used reduced emissions completions in only 29 percent of natural gas wells in the United States, the filing said. By comparison, Chevron, the second-most profitable American company, told CDP it used such completions in 90 percent of its natural gas wells in 2013.

Exxon Mobil left that question blank.

ConocoPhillips said that it significantly curbed pollution in 2014, the year following ClimateWire's analysis. Its preliminary numbers show that carbon emissions in the San Juan Basin dropped by nearly half, a spokeswoman said.

Methane emissions from liquids unloading in the San Juan fell by 66 percent since 2013, and emissions from pneumatic devices fell by 59 percent, she said.

The company is now replacing all high-bleed pneumatic devices with lower-bleed devices, she said.

"Over the last few years, we have taken proactive steps to reduce emissions companywide, including in the San Juan Basin," she said.

Corroborating these statements would take another year, as EPA is still finalizing its greenhouse gas database for 2014.

Reporter Benjamin Hulac contributed.