I’m not sure if you have seen the new EPA report on emissions related to natural gas, but for those who are not familiar with the data under discussion the conclusion is misleading.
First and foremost, though, kudos to the EPA for looking at upstream emissions for comparing natural gas to other options. The problem, however, is that the actual data used is limited and may even inflate methane emissions by several orders of magnitude.
The EPA and everyone else in the industry has been using “emission factors” developed long ago to estimate how much methane leaks from production wells, pipeline valves and the like. It’s common knowledge that these emission factors were based on very limited field testing performed nearly 20 years ago, and that they are seriously in need of updating and refinement. The EPA even addresses this issue of outdated data in its November 2010 Technical Support document. However, without any support to back up the claim, the EPA then claims that emissions today may be higher than they were 20 years ago.
Not only is such a statement wholly unsupported by any data, it’s actually in opposition to recent findings. EPA’s Natural Gas STAR program managers, fully aware of the problem with outdated information, took steps about four years ago to launch a joint research project with energy industry trade groups to do new, more extensive field testing on modern natural gas systems to see what is really going on and to develop updated emission factors.
That work has already resulted in some new emission factors for natural gas distribution and transmission equipment, and other work is continuing this year and next. The work so far shows that methane emissions are declining as natural gas systems become tighter as the result of new technology, equipment and procedures.
And let’s not forget that even using the old inflated emission factors, EPA estimates that natural gas is more efficient and lower emitting than other options.
