Dear EarthTalk: I heard someone say that the environmental benefits of natural gas for electricity generation were overstated, and that it is not as green-friendly as the industry would have us believe. What is your take on this?—D. Montcalm, Brewster, N.Y.
In our increasingly carbon-constrained world, natural gas (also known as methane) does keep coming up as a potentially cleaner fuel source for electricity generation than coal, currently the nation’s primary source of electrical power. Natural gas advocates argue that it generates 50 percent fewer greenhouse gases than coal when burned. And since natural gas is more widely available than ever, thanks to newer more efficient—though in some cases environmentally damaging—extraction techniques, some think it should be playing a larger role in a transition away from coal, the dirtiest of all fossil fuels. Today over 50 percent of electricity generated in the U.S. comes from coal; natural gas accounts for less than 20 percent.
But scientists aren’t so sure natural gas should play any part in solving the climate crisis. A 2007 lifecycle analysis of natural gas production, distribution and consumption found that when one factors in the total emissions associated with not only the end use of natural gas but also its extraction and distribution—much of it can leak when it is pulled out of the ground and then piped to power plants and other customers—it doesn’t seem so much cleaner than coal after all.
The U.S. Environmental Protection Agency (EPA) says that loose pipe fittings and intentional venting for safety purposes on natural gas lines cause annual greenhouse gas emissions rivaling that produced by 35 million cars each year. The World Bank estimates that emissions from natural gas extraction operations alone account for over a fifth of the atmosphere’s total load of climate-changing methane.
“When scientists evaluate the greenhouse gas emissions of energy sources over their full lifecycle and incorporate the methane emitted during production, the advantage of natural gas holds true only when it is burned in more modern and efficient plants,” reports Abrahm Lustgarten on the investigative news website, ProPublica. “But roughly half of the 1,600 gas-fired power plants in the United States operate at the lowest end of the efficiency spectrum.”
He adds that, while the median U.S. gas-fired power plant emits 40 percent fewer greenhouse gases than a typical coal plant, some 800 inefficient plants offer only a 25 percent improvement. The fact that methane is an extremely potent greenhouse gas—the EPA says methane is 20 times more effective trapping heat in the atmosphere than carbon dioxide (CO2) —makes it even less appealing as a replacement for coal.
“The problem is you build a gas plant for 40 years,” James Rogers, CEO of Duke Energy, one of the largest power companies in the U.S., told ProPublica. “That’s a long bridge. What if, with revelations around methane emissions, it turns out to be only a 10 or 20 percent reduction of carbon from coal? If that’s true, gas is not the panacea.” Rogers himself is an advocate for limiting greenhouse gas emissions.
But with the Obama administration still keen on mining domestic natural gas reserves versus upping our reliance on foreign oil, natural gas will likely continue to play a role in the energy mix for some time yet.
CONTACTS: ProPublica, www.propublica.org; Duke Energy, www.duke-energy.com.
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9 Comments
Add CommentI think you're supposed to only count the emissions at the use point, not the production and delivery emissions. That's they way the electric car people do it...
Reply | Report Abuse | Link to thisActually the methane contribution is 75 times CO2 during its first 20 years. The 20 times is its average over a 100 years or so.
Reply | Report Abuse | Link to thisSince the next 20 years is critical..............
Sadly, @lamorpha is right. In our one-dimensional, capitalist age, the holistic view of how the world works rarely comes into play. Instead, we look at point-source and the easy-to-track Scope 1 emissions (that's greenhouse gas management talk, sorry). Instead, we need to do a supply chain analysis of everything that we do to produce energy: solar, wind, biofuels, all of it, to make a truly educated decision on what is more 'costly' both economically and environmentally. But information continues to be sparse and to be murky because of broken systems, human laziness, and economic indicators ruling out any sensibility.
Reply | Report Abuse | Link to thisI commend Scientific American for revealing that natural gas leaks are a part of the industry because so often, it is seen as a panaceaic 'solution'. But when it comes down to it, it is a distraction from real sources of sustainable energy.
Nature has been teaching us this lesson for millions of years; why is it when we dig in the ground and discover million-year-old sunlight, we stopped listening? Photosynthesis, people! Harness it. More solar energy falls on the earth in one day than we can use for an entire year. So, even if photosynthesis is only 1% efficient, if we can harness it for 100 days per year, we're set!
Biofuels (grown on non-arable, non-prime, non-agricultural land, such as the ditches of highways that could easily be harvested) and alcohol are so much easier and sustainable. But we still want to squeeze out "cheap" (economically, but not environmentally) fossil fuels which puts the burden on to other parts of the world, other periods of time, other species, plants, etc. We shift the burden due to laziness. It is bad policy. Live within your means, fiscally, environmentally, and when it comes to energy. Energy is plentiful in the now, but the systems we have are inefficient and predicated on economic, rather than long-term indicators. If energy were 1000$/kJ, our economies would eventually adjust. We ALWAYS adjust: that is our strength as humans.
Population control is the only answer. The rest is just pandering to idiots who think they know everything, mostly because some fairy god told them so.
Reply | Report Abuse | Link to thisAs I understand, during the boom years (decades) of oil discovery it was common practice to simply vent all the pesky gas into the atmosphere so the drillers could pump the oil out. I don't promote the use of natural gas, but I doubt there's enough gas left now to match the intentional releases of previous decades or centuries.
Reply | Report Abuse | Link to thisI flew at night over most of the oil producing countries of the middle east in the late 1960s. These areas were a forrest of fire from the gas burn off associated with the oil. An unwanted byproduct at that time.
Reply | Report Abuse | Link to thisI'd forgotten that they also/mostly burned the waste gas off. I presume the combustion products (co2) were less harmful than the earlier methane releases? I think the oil rig workers were justifiably concerned about accidental NG explosions...
Reply | Report Abuse | Link to thisthedr9wningman: you start off fine, but then you fail to apply the tests you recommend to your own ideas. If you did, you would see that an awful lot of energy would be expended in planting and harvesting the distributed crops. You must also be aware that at the moment there's no tried and tested way of converting cellulose to useful energy: current biofuels use sugar-rich crops. And you are totally underestimating the areas which would be needed to produce useful amounts, areas which will be desperately needed for food.
Reply | Report Abuse | Link to thisThere have been articles in Sciam on this (cf. switchgrass).
Natural gas starts out with the same major problem as coal, oil and uranium. The extractive processes used to remove these fuel sources produce gross amounts of waste and pollution, added to the carbon and radioactive mass that becomes fuel.
Reply | Report Abuse | Link to thisAll the cap and trade and so-called sequestration will never neutralize this addition to the existing carbon, in all its forms that make up our environment.
Then you add in all the energy (mostly petroleum based) used in extracting the base products, transporting and refining them, and most significantly, the 2/3 waste of these fuel products in the form of excess heat that also requires more energy to dissipate at the power plant and you are left with a lot of hidden costs (not even mentioning the environmental problems) that are shoveled over with various tax incentives.
The need for efficiency and conservation has never been greater.