Methane can only be visibly detected by imaging or high-end technological equipment.
Inefficient flaring releases methane when gas is burned and converted to less potent CO2.
When gas is burned, it releases 50 percent less carbon dioxide into the atmosphere than coal.
Therefore, most people assume it has half the climate impact as coal.
But this doesn’t account for methane leaks.
Over a 20-year period, it traps over 82.5 times more heat than carbon dioxide (CO2).
Methane leakage is caused by the malfunction of compressors, pumps, and valves...
...and by intentional releases (venting and flaring). Leakage is measured as a percentage of total natural gas produced.
When methane leakage from gas systems is included, the climate benefit of gas compared to coal flips. Methane leakage as low as 0.2% can bring gas' net GHG emissions on par with coal.
However, studies are finding that the EPA estimate of methane leakage is too low because it uses generic leakage factors and incomplete measurements from ground based equipment.
Technology mounted on airplanes and satellites has provided more accurate methane emissions measurement at larger scale.
Over the past 5 years, several studies using this technology have been published. They reported methane leakage rates from 1.2 to 11 percent.
Aerial measurements can vary widely because of super emitters—big leaks that disproportionately contribute to regional emissions.
This indicates that natural gas may not have any climate advantage over coal with the current rate of methane leakage.
Leaky gas is even worse than coal. Stopping gas from leaking can be done profitably by cutting waste and preventing it from escaping into the atmosphere.
Reducing US methane leakage from gas systems to minimum levels would be equivalent to taking all US cars off the road for a year.