Porter Ranch methane leak decreased by 60 percent

The California Air Resources Board (CARB) estimates that methane emissions from the Aliso Canyon decreased by 60 percent since November 28.

Preliminary methane emissions based on CARB data collected on Jan. 8 and posted yesterday show emissions have declined to 23,400 kilograms per hour from a high estimate of 58,000 kilograms on November 28, according to information posted on the CARB web site.

CARB also calculated the total estimated volume of greenhouse gas (GHG) released from the well since the leak was detected at 1.9 million metric tons in carbon-dioxide equivalent. According to CARB’s report on annual GHG emissions in California, the estimated total from the Aliso leak is less than one-half of 1 percent (0.4 percent) of California’s total annual GHG emissions in carbon-dioxide equivalent.

SoCalGas is reiterating its intent to mitigate the environmental impact of the actual amount of natural gas released from the leak.