The recent natural gas boom has divided the green community. While some see an environmental train wreck, others envision a bridge to wind and solar. Either way, the transition to a zero carbon energy future could get uncomfortable.
By John Carey
Climate change may be one of the biggest threats facing humankind, but the United States government hasn’t gotten the message. Congress nixed a cap-and-trade bill in 2010 that would have reduced emissions of the greenhouse gases that cause planetary warming. Taxes on carbon, or national mandates to boost renewable electricity generation, have been nonstarters. And even though the feds raised fuel economy standards for cars and trucks, the Environmental Protection Agency has delayed setting CO2 emissions limits on power plants.
Yet even as Washington has remained mired in climate paralysis, something surprising has happened. Greenhouse gas emissions in the U.S. have declined by about seven percent between 2005 and 2011. In 2012, the U.S. Energy Information Administration reported that CO2 emissions in the U.S. had hit a 20-year low. Why? The causes include the Great Recession, growth in wind and solar power, and improved energy efficiency. Many experts say the single biggest reason, however, has been an unexpected flood of cheap natural gas extracted from shale by a technique called hydraulic fracturing or fracking. This vast new supply has prompted utilities to switch from burning coal to burning gas, which roughly halves the CO2 emissions for every unit of electricity produced. “Coal and gas are duking it out—and the evidence is pretty overwhelming that there is a climate advantage of using gas instead of coal,” says Michael Webber, deputy director of the Energy Institute at the University of Texas at Austin.
That’s why Webber and a number of other experts see natural gas as a game-changer and a golden opportunity to build an inexpensive bridge to a low carbon energy future. Recent reports from organizations as disparate as banking giant Citigroup and the Breakthrough Institute, which bills itself as a paradigm-shifting environmental think tank, argue that natural gas is a crucial transition fuel. (1,2) Gas provides an “abundant and (potentially) cheap source of energy to be used while renewables continue to gain in competitiveness,” says the Citigroup report. Far from undercutting wind, solar, and other renewables, “gas and renewables could in fact be the making of each other,” the report says. Gas is good. “We need to actually double down on the natural gas revolution,” argues Ted Nordhaus, cofounder and chairman of the Breakthrough Institute.
Wrong and dangerous, retort many scientists and mainstream environmentalists. Rushing to gas “would be just deadly from a climate standpoint,” says Robert Howarth, professor of ecology and environmental biology at Cornell University. Natural gas (or methane, as it is also called) is itself a potent greenhouse gas. In a controversial study published in 2011, Howarth and his colleagues found that enough methane may be released during the drilling and transport of natural gas to wipe out any climate benefits from burning gas instead of coal. (3) That study, and other evidence for gas dangers, has turned some enviro groups, such as the Sierra Club, from cautious supporters of the natural gas bridge idea into foes. Claiming that natural gas is more climate-friendly than other fossil fuels is “like saying it’s safer to be attacked with a knife than a gun,” argues Sierra Club executive director Michael Brune. “If you end up dead, it’s a moot point.” Or as Greenpeace US executive director Philip Radford says: “Any new natural gas is a bridge fuel to nowhere.”
This contentious debate is playing out not just at the national level, driving a wedge into the green community, but in states as well. In developing a new energy plan last year, Connecticut energy officials debated whether to seize the opportunity presented by natural gas to switch homes, businesses, and facilities such as factories and schools from dirty and expensive fuel-oil heating to cleaner, cheaper gas—a move that would require a major expansion of gas infrastructure. The debate was heated, recalls Stephen Doig, senior expert at McKinsey & Company, who worked on the plan when he was with the Rocky Mountain Institute. “Some people saw natural gas as the savior; others thought it was the nail in the coffin,” he says. The central question: Would new gas mains lock the state into natural gas dependency for decades, closing off even cleaner options such as high-efficiency heat pumps? Nope, state officials decided, recommending building 900 miles of gas mains.
What makes the issue of natural gas even more difficult is that gas is a major economic boon as well as a long-term question mark. The sudden availability of huge amounts of cheap gas has prompted companies, among them Dow Chemical, to invest billions of dollars in new facilities in North America, for instance. “For the first time, the U.S. has this amazing once-in-a generation competitive advantage,” says Peter Molinaro, Dow’s vice president for North America government affairs. Former Obama administration budget director Peter Orszag pegs the benefit of new domestic gas and oil production to the nation’s economy at $100 billion a year—“basically a $100 billion tax cut,” he says. Of course, there are no guarantees for how long this economic boost will last. Just as experts failed to predict the gas spike to $13 per thousand cubic feet in 2008 or the subsequent plunge to less than $3, the only sure bet about the future is that there will be surprises. “We’re awful at predicting our energy future,” says Michael Levi, director of the program on energy security and climate change at the Council on Foreign Relations and author of The Power Surge: Energy, Opportunity, and the Battle for America’s Future.
So what do we actually know? Is natural gas a bridge to a better climate future or a dangerous detour?
The argument for the bridge starts with a key theme in human history: a continued march toward cheaper, better fuels. Wood reigned supreme for millennia. Then coal, being cheaper and better, made the industrial revolution possible. Oil was even more efficient and versatile, explaining why it’s been the dominant fuel for the past 60-plus years. Each fuel was a solution to the challenges of the times, and each created new environmental problems.
Now, natural gas is today’s economic and environmental solution and tomorrow’s problem, says UT’s Webber. Utilities have been shutting down scores of old, dirty coal plants and turning instead to natural gas–fired generation. As a result, coal’s share of U.S. electricity production has dropped from 48.5 percent in 2007 to 37.4 percent in 2012. Natural gas’s share has risen from 21.6 percent in 2007 to 30.4 percent in the same period. That shift is saving money and reducing both air pollution and greenhouse gas emissions from power plants. “Would we be better off if energy is based on natural gas than coal? The answer is yes,” says CFR’s Levi.
But wouldn’t the climate be even better off if we just skipped gas and doubled down on renewables and energy efficiency instead? Indeed, gas critics fear that a dash to gas is slowing the growth of renewable energy. That’s hard to prove, since other policies—such as tax credits and state renewable portfolio standards—as well as declining prices for solar and wind are key drivers of the pace of adoption. And the data don’t show an obvious slowdown. Solar power grew by 34 percent in 2012 and wind by 16 percent, while Bloomberg New Energy Finance predicts continued rapid growth in renewable investments despite competition from gas.
Moreover, bridge fuel proponents argue that far from being antagonists, renewables and natural gas need each other. “They solve each other’s problems,” says Webber, who worked with the Center for Climate and Energy Solutions (C2ES) on a new report, “Leveraging Natural Gas to Reduce Greenhouse Gas Emissions.” (4) Electricity from wind farms or solar panels cuts off when the wind dies or the sun doesn’t shine. Balancing supply and demand on the electricity grid thus requires a source of power that can be ramped up almost instantly. Natural gas plants, unlike nuclear or coal facilities, can be that source. “Cheap gas helps rather than undermines the development and deployment of zero carbon energy sources like solar and wind,” argues the Breakthrough Institute’s report, “Coal Killer: How Natural Gas Fuels the Clean Energy Revolution.”
The big worry for users of natural gas is that prices might suddenly double or triple, as they’ve done in the past. That’s why solar and wind are crucial. With no fuel costs, they moderate the economic hit from price spikes. Eventually, the gas bridge advocates predict, the cost of wind and solar will drop enough for renewables to become the cheaper, better source of energy—especially if (or more likely, when) natural gas prices climb significantly. Then the nation can finally cross over to the zero carbon energy future. Sure, capital investments in gas infrastructure would essentially lock the country into using gas for decades, “but if we can get off of gas in 40 years, that would be very fast in my opinion,” says Webber.
Gas supporters readily admit this bridge isn’t the fastest possible route to fighting climate change. “It is a bridge in the direction of decarbonization; it’s just not as big a step as many people want,” says Webber. But it’s important not to let the perfect be the enemy of the good, advocates say. A transition period using natural gas can help stabilize atmospheric concentrations of CO2 at 550 parts per million (up from today’s peak of 400 ppm and the 260 to 270 ppm of preindustrial times), a recent analysis by Levi shows, though it’s of little or no help in limiting concentrations to 450 ppm. (5)
Plus, there’s widespread agreement among those calling for action on climate that whatever happens with gas, the nation still needs aggressive policies, such as a carbon tax or renewable mandates, to encourage low carbon energy and increased efficiency. The Breakthrough Institute, for instance, recommends using billions of dollars in economic savings from gas to “pay forward the shale gas revolution by making long-term investments in innovation of renewables and nuclear energy.” Others, like Peter Orszag, say that the crucial missing piece is a price on carbon. “Gas provides an opportunity to make better policy, but it is not a solution in itself,” says Levi. “I worry that if we think gas is solving our climate problems, we can get lazy on climate.”
To some scientists and environmental groups, however, the natural gas bridge isn’t just imperfect. It’s the wrong path entirely. The main reason, they say, is that natural gas doesn’t just contribute to planetary warming through its CO2 emissions when burned. Methane also leaks out during drilling, distribution, and storage in what are called “fugitive” emissions. This methane doesn’t stay in the atmosphere long, with a lifetime of about 12 years compared to 100 years for CO2, but it’s a more potent greenhouse gas. Even calculated over a period of 100 years, methane emissions trap up to 33 times more heat than the same amount of CO2 by some estimates. Using a 20-year time frame, which some scientists argue is more appropriate because today’s warming could lead to climate tipping points, the warming potential jumps to more than 100 times that of CO2. “Regardless of the time scale, if you exploit natural gas and let a bunch of methane leak out, it is a really bad thing from the climate point of view,” says atmospheric scientist Drew Shindell of NASA’s Goddard Institute for Space Studies.
Methane is indeed leaking out—though the actual amount is fiercely disputed. Cornell’s Howarth kicked off a raging debate when the team he led calculated in 2011 that 3.6 to 7.9 percent of the gas fracked from shale deposits escapes before it is burned. Even without adding in the planetary cooling from reflective sulfate particles emitted by burning coal, that could be enough methane to more than offset the lower amount of CO2 emitted when gas is burned instead of coal to generate electricity. “It is totally misleading to say natural gas causes less warming than coal,” says Mark Jacobson, director of Stanford University’s Atmosphere/Energy Program. “The point is that they are both bad and need to be replaced immediately.”
Howarth’s study has been vigorously attacked. A subsequent commentary in Climatic Change, where Howarth’s paper was originally published, charged that the study was “seriously flawed,” arguing that it overestimated the amount of lost methane and undervalued green technologies that minimize leaks. (6) Meanwhile, the EPA estimated fugitive methane leakage in April 2012 to be 2.3 percent. More recently, in April 2013, they lowered that estimate to 1.4 percent, pointing to tighter pollution controls within the industry. The EPA’s estimates, however, have drawn criticism for including data from an industry-funded report. The debate has prompted a growing effort to independently measure methane emissions out in the field, but most of those studies have yet to be published. Some show unexpectedly high methane concentrations. In one new study, for instance, researchers “found large methane sources over Texas, Oklahoma, and Louisiana” and suggested that most of the published studies “significantly underestimate” methane emissions and thus the greenhouse gas footprint from natural gas.
The purported climate benefits of using more gas shrink even more when indirect effects are considered. In yet another twist in this complex tale, cheap gas is not only displacing coal, it’s threatening the profitability of nuclear power plants, which emit no greenhouse gases at all. Natural gas is “wiping out the nuclear industry quicker than we thought,” says David Crane, CEO of New Jersey–based power giant NRG Energy. In addition, the replacement of coal by natural gas in the U.S. doesn’t necessarily even trim CO2 emissions from burning coal, since much of the coal not used at home is simply exported and burned in other countries. In 2012, U.S. coal exports climbed significantly.
The view that natural gas may actually be a Faustian bargain on climate is having one somewhat ironic result: it’s helped ease a thorny dilemma for some environmentalists. As Sierra Club executive director Brune points out, “For most environmental organizations, as well as most policy makers, gas was thought of as a fuel with less harmful qualities compared to oil and coal.” Supporting increased natural gas use, however, put enviro groups’ national climate teams at odds with their local activists, who have been opposing fracking because of concerns over water quality and other environmental harm. If natural gas is bad for the climate, too, those internal conflicts vanish. The Sierra Club, for instance, is now fighting both fracking and the construction of new natural gas plants in its “Beyond Natural Gas” campaign.
For the rest of the country, however, the doubts over a natural gas bridge make the dilemma more acute. True, a serious fight against climate change demands many of the same policies—such as a price on carbon and other policies that boost energy efficiency measures and the growth of renewable energy—regardless of the role natural gas will play. In addition, the rush to natural gas is already occurring, whether people like it or not, so the nation needs regulations to crack down on methane leaks.
While these measures seem obvious to anyone concerned about climate change, the odds for action in Washington within the next few years are slim to none. And in the meantime, tough choices are already looming. Should the nation build new natural gas power plants and pipelines and hook up millions more homes and businesses to gas mains, hoping that the natural gas bridge is the best path to protecting the planet? Or should the U.S.—and indeed the entire world—aim to leapfrog gas with a powerful push toward a zero carbon energy future?
There’s no agreement on the right answer. One set of experts argues we have no choice but to use natural gas as a transition fuel, since renewables “aren’t ready for prime time,” as UT’s Webber says. Another group, which includes Stanford’s Jacobson and Cornell’s Howarth, is already charting detailed paths for weaning U.S. states entirely from fossil fuels. “Converting to wind, water, and sunlight is feasible,” insists Jacobson.
The nation is already inching out on the natural gas bridge. But for our future climate, there’s no time to linger. ❧
Veteran science and environment writer John Carey has served as a senior correspondent in Business Week’s Washington Bureau, as an editor for The Scientist, and as a writer for Newsweek, where he covered science, technology, and health.
1. Channell, J., T. Lam and S. Pourreza. 2012. Shale and renewables: A symbiotic relationship. Citigroup report (pdf).
2. Coal killer: How natural gas fuels the clean energy revolution. The Breakthrough Institute, April 2013.
3. Howarth, R., R. Santoro and A. Ingraffea. 2011. Climatic Change doi:10.1007/s10584-011-0061-5.
4. Leveraging natural gas to reduce greenhouse gas emissions. 2013. Center for Climate and Energy Solutions report.
5. Levi, M. 2013. Climatic Change doi:10.1007/s10584-012-0658-3.
6. Cathles III, L.M. 2012. Climatic Change doi:10.1007/s10584-011-0333-0.
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