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, NY
A 2007 life-cycle analysis of natural
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.
Dear EarthTalk: Isn’t it a waste that we buy water in plastic bottles when it is basically free out of our taps? Even health food stores, which should know better, sell it like crazy. When did Earth’s most abundant and free natural resource become a commercial ‘beverage’? -- A. Jacobs, via e-mail
|According to the Earth Policy Institute,
some 2.7 million tons of petroleum-derived
plastic are used to bottle water around the
world every year. Photo courtesy Ryan
Bottled water has been a big-selling commercial beverage around the world since the late 1980s. According to the Worldwatch Institute, global bottled water consumption has more than quadrupled since 1990. Today Americans consume over 30 billion liters of water out of some 50 billion (mostly plastic) bottles every year. The Beverage Marketing Association reports that in 2008 bottled water comprised over 28 percent of the U.S. liquid refreshment beverage market. The only bottled drinks Americans consume more of are carbonated sodas like Coke and Pepsi.
And frankly, yes, it is a ridiculous waste that we obtain so much of our drinking water this way when it is free flowing and just as good if not better for you right out of the tap. According to the Earth Policy Institute (EPI), some 2.7 million tons of petroleum-derived plastic are used to bottle water around the world every year. “Making bottles to meet Americans’ demand for bottled water requires more than 1.5 million barrels of oil annually, enough to fuel some 100,000 U.S. cars for a year,” says EPI researcher Emily Arnold. And just because we can recycle these bottles does not mean that we do: The Container Recycling Institute reports that 86 percent of plastic water bottles in the U.S. end up as garbage or litter.
The financial costs to consumers are high, too: According to the Environmental Working Group (EWG), bottled water costs up to 1,900 times more than tap water. And the Natural Resources Defense Council (NRDC) reports that 90 percent or more of the money consumers shell out for it pays for everything but the water itself: bottling, packaging, shipping, marketing, other expenses—and, of course, profits.
EWG is particularly appalled at the lack of transparency by leading bottled water sellers as to the sources of their water and whether it is purified or has been tested for contaminants. According to a recent survey by the group, 18 percent of the 173 bottled waters on the U.S. market today fail to list the location of their source; a third disclose nothing about the treatment or purity of the water inside their plastic bottles.
“Among the ten best-selling brands, nine—Pepsi’s Aquafina, Coca-Cola’s Dasani, Crystal Geyser and six of seven Nestlé brands—don’t answer at least one of those questions,” reports EWG. Only Nestlé’s Pure Life Purified Water “discloses its specific geographic water source and treatment method…and offers an 800-number, website or mailing address where consumers can request a water quality test report.”
EWG recommends that consumer resist the urge to buy bottled water and go instead for filtered tap water. “You'll save money, drink water that’s purer than tap water and help solve the global glut of plastic bottles,” the group advises, adding that it supports stronger federal standards to enforce consumers’ right to know about what’s in their bottled water besides water. Until that day comes, concerned consumes should check out EWG’s Bottled Water Scorecard, a free website that provides information on various bottled water brands, where they originate and whether and how they are treated to remove contaminants.