Here is the story in today's NYT about the University of Texas methane leakage study:
Here is the link to the study published by the Proceedings of the National Academy of Science:
The study was done in collaboration with the Environmental Defense Fund and 9 drilling companies. It's method was actual measurement of emissions at 150 drilling sites, containing 489 wells that were all hydraulically fractured, located in a variety of regions across the United States.
The study extrapolates from its measurements to conclude that methane leakage amounts to 0.42% of gas produced, considerably lower than the most recent Environmental Protection Agency estimate.
This study is an important contribution to defining the methane leakage problem and further reducing methane leakage. And further reducing methane leakage, as well as flaring and other air pollutants from gas production, should be a goal that most would support.
Is the study definitive or the last word? Absolutely not and more research will be done.
It took measurements at about 2% of the gas wells drilled in a year. It involved the voluntary cooperation of 9 drilling companies and has a possible self-selection bias. The methane leakage performance at these wells is good, though it could be better, and may be representative of good performing companies and wells.
As such, the study may be the best case scenario that identifies an achievable standard of excellence that should become a requirement for all gas drilling companies to meet. Simply put, if these shale gas wells can perform at this low level of leakage, then all shale gas wells that are hydraulically fractured should be able to do so.
What the study does show definitively is that "green completions" work very well, reducing methane leakage by 99%. And the EPA rule on green completions takes affect in January 2015. That is good news, indeed.