Wednesday, December 24, 2014

Gas Leaks:

Is Natural Gas As Clean As We've Thought?

Just after I posted my previous post, which cited a study showing that nuclear power, hydroelectricity and natural gas were "better" than solar and wind power, I came across an interesting study that suggests that natural gas could result in greater global warming than coal plants!

Their argument is that methane leaks in natural gas systems may make actually put more carbon in the atmosphere than coal plants do.  I need to emphasize that this study appears to be based on hypothetical calculations.  Both the news article cited above and the abstract to the paper show what the emissions curves from natural gas plants look like compared to coal plants based on varying assumptions about leakage rates, but do not indicate what the actual leakage rates are or how hard it would be to control them.  Nor is it clear how they account for the different effects of methane and carbon dioxide in the atmosphere--specifically, the fact that methane is a more potent greenhouse gas, but has a shorter half-life in the atmosphere.

On the one hand, a problem identified may be a problem on its way to resolution, so it is not clear to me how serious this concern might be.  Maybe testing will show that there is little or no leakage.  Maybe any leaks in existing facilities can be plugged.  Maybe new designs and new materials, or better construction, can limit leaks in the future. 

On the other hand, we already have heard other reports of leakage from pipelines and oil wells, so we do know that leakage is a difficult problem, and with thousands and thousands of miles of pipelines, those leaks could be a difficult and costly problem to solve.  And sadly, even shutting those systems down is not necessarily sufficient, as studies also show that there is significant methane leakage from abandoned oil and gas wells.  And in this case, the results are based on tests of wells that have been shut down, so we know that it is a real problem.

Nevertheless, with this report coming to my attention hard on the heels of the report showing the benefits of nuclear, hydro and natural gas over wind and solar, the news that natural gas may have more emissions than we've been assuming made me start to wonder:  We already know that the potential for adding significant amounts of hydroelectric power are limited--and even where it is possible, that comes with other environmental impacts.  So...which energy technology will be the last one left standing?

It is way too soon to answer that, of course.  In the first place, we need to find out what the actual leakage rates are.  So I'm not writing off natural gas just yet.  In fact, I sincerely hope the calculations do not turn out to be true, because it is clear that we have a transition period ahead of us to reduce our use of coal, and we need a variety of options to make that transition.

Nevertheless, seeing this report reminded me once again how complex the energy situation is.  It seems that, just when we think we have found "the" solution, we always discover a factor we didn't consider.  Methane leakage from natural gas plants could become such a factor.  Stay tuned!


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