Evidence grows of no net climate benefit from gas.

Climate Progress: “The evidence is mounting that natural gas has no net climate benefit in any timescale that matters to humanity. In the real world, natural gas is not a “bridge” fuel to a carbon-free economy for two key reasons.”
“First, natural gas is mostly methane, (CH4), a super-potent greenhouse gas, which traps 86 times as much heat as CO2 over a 20-year period. So even small leaks in the natural gas production and delivery system can have a large climate impact — enough to gut the entire benefit of switching from coal-fired power to gas.
Sadly as a comprehensive new Stanford study reconfirms, “America’s natural gas system is leaky.” The news release explains: A review of more than 200 earlier studies confirms that U.S. emissions of methane are considerably higher than official estimates. Leaks from the nation’s natural gas system are an important part of the problem.
Second, natural gas doesn’t just displace coal — it also displaces carbon-free sources of power such as renewable energy, nuclear power, and energy efficiency. A recent analysisfinds that effect has been large enough recently to wipe out almost the entire climate benefit from increasing natural gas use in the utility sector if the leakage rate is only 1.2 percent (comparable to the EPA’s now discredited new lowball estimate).
In fact, as a major paper we reported on in November found, “The US EPA recently decreased its CH4 emission factors for fossil fuel extraction and processing by 25–30% (for 1990–2011), but we find that CH4 data from across North America instead indicate the need for a larger adjustment of the opposite sign.”
The new study in Science “Methane Leaks from North American Natural Gas Systems” (subs. req’d) is even more problematic for natural gas as a so-called bridge fuel.
Because the study is a consensus paper from a variety of authors and because the data on leakage rates is not high quality, the paper itself does not suggest a revised natural gas (NG) leakage rate. But the Supplementary Materials do. Deep on page 29 is a section titled, “Calculating leakage percentages associated with possible NG leakage,” where the authors explain that they “can put bounds on the possible leakage rates from the NG system.” Their analysis finds:
“… an excess percentage leakage of 1.8% to 5.4% of end use gas. Coupled with the current estimate of 1.8% leakage of end use gas consumed, this generates a high-end estimate of 7.1% gas leakage.”