“For short time frames and if natural gas leakage rates are high, natural gas may offer little benefit compared to coal or could even exacerbate warming,” according to economist Chris Busch and physicist Eric Gimon, publishing in the most recent issue of The Electricity Journal. ”Over a longer period, such as 100 years or more, natural gas from electricity provides greenhouse gas reductions compared to coal even if leakage rates are relatively high.”
The advantage of natural gas can best be seen over the long-term, in which gas offers about a 50 percent reduction in emissions over coal. Unfortunately, a 50 percent improvement over 100 years is too little, too late.
“By this time, emissions reductions must be much more ambitious than this if we are to power civilization in a way that enables a safe and stable climate,” according to an issue brief released in conjunction with the study.
Although natural gas produces about half the carbon emissions of coal, methane leaks at every stage of the natural-gas lifecycle, and methane traps heat in the atmosphere about 120 times more effectively than carbon dioxide.
Other studies have estimated that up to 4 percent of natural gas leaks into the atmosphere before it reaches power plants, and this study concludes that leakage negates much of gas’s advantage.
“Under the best of circumstances, natural gas-fired electric power plants can only make a modest dent on abating climate change—and, if developed poorly, with serious methane leaks, or if used to displace energy efficiency or renewable energy, natural gas could instead seriously contribute to the problem.”
The Environmental Protection Agency counts on the advantages of natural gas in its draft Clean Power Plan, released earlier this year. Another article in the current issue of The Electricity Journal anticipates that “EPA’s Proposed Rule Could Prompt a Larger-than-Expected Shift from Coal to Gas by 2020.”
The new study supports concerns by environmentalists about the Obama Administration’s confidence in a natural gas bridge. For example, earlier this month in Mother Jones Bill McKibben writes that “President Obama’s climate change strategy is starting to unravel even as it’s being knit.”
Seeming to understand its vulnerability on this point, the White House released a “Strategy to Cut Methane Emissions” earlier this year, and the EPA has increased attention on methane leaks in a series of studies and white papers of its own.
