Post by Roger Clifton on Dec 15, 2013 16:24:46 GMT 9.5
Nuclear's link (cited above) reports on a gas-industry sponsored visit to selected gas production sites, with predictably good marks reported. Here, more respectably, is a peer-reviewed study from Geophysical Research Letters, showing a leakage rate during production of between 6 and 12%. Although the article is behind a pay wall, the abstract says that such emissions "have the potential to offset the climate benefits of natural gas over other fossil fuels."
The survey was conducted with scanning instruments from an aircraft over a natural gas production field, the variation being between well sites. The paper says "this leak rate is nearly twice the rate estimated… by the Government Accountability Office". It also says that "this high leak rate probably negates any immediate climate benefits of using natural gas instead of coal or oil and represents a possible air pollution hazard" (my italics), as reported in Eos 15 October 2013. This is because methane is between 20 and 100 times more damaging to the greenhouse than CO2, depending on the time interval measured.
These leakages are from production, whereas additional losses during distribution also occur. Methane leaks from long-distance pipelines at rates of between 1 and 2%, and more again from municipal gas lines. While leakages from long-distance pipelines can be tracked and attributed from aircraft, the (mixed) sources of methane leakages in a city are harder to identify. However, the frequency of city gas explosions attributed to leaking gas mains does suggest it is a lot more than negligible.
The survey was conducted with scanning instruments from an aircraft over a natural gas production field, the variation being between well sites. The paper says "this leak rate is nearly twice the rate estimated… by the Government Accountability Office". It also says that "this high leak rate probably negates any immediate climate benefits of using natural gas instead of coal or oil and represents a possible air pollution hazard" (my italics), as reported in Eos 15 October 2013. This is because methane is between 20 and 100 times more damaging to the greenhouse than CO2, depending on the time interval measured.
These leakages are from production, whereas additional losses during distribution also occur. Methane leaks from long-distance pipelines at rates of between 1 and 2%, and more again from municipal gas lines. While leakages from long-distance pipelines can be tracked and attributed from aircraft, the (mixed) sources of methane leakages in a city are harder to identify. However, the frequency of city gas explosions attributed to leaking gas mains does suggest it is a lot more than negligible.
