In November the EPA announced new greenhouse gas reporting rules for the oil and gas industry. For the first time under the Clean Air Act, the nation's guiding air quality law, thousands of small facilities will have to be counted in the pollution reporting inventory, a change that might also lead to higher measurements.
The natural gas industry, in the meantime, has pressed hard for subsidies and guarantees that would establish gas as an indispensible source of American energy and create a market for the vast new gas reserves discovered in recent years. The industry would like to see new power plants built to run on gas, automobile infrastructure developed to support gas vehicles and a slew of other ambitious plans that would commit the United States to a reliance on gas for decades to come.
But if it turns out that natural gas offers a more modest improvement over coal and oil, as the new EPA data begin to suggest, then billions of dollars of taxpayer and industry investment in new infrastructure, drilling and planning could be spent for limited gain.
"The problem is you build a gas plant for 40 years. That's a long bridge," said James Rogers, CEO of Duke Energy, one of the nation's largest power companies. Duke generates more than half of its electricity from coal, but Rogers has also been a vocal proponent of cap-and-trade legislation to limit greenhouse gas emissions.
Rogers worries that a blind jump to gas could leave the country dependent on yet another fossil resource, without stemming the rate of climate change.
"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," he said, "gas is not the panacea."
The American Petroleum Institute said in an e-mailed response that federal offshore drilling rules are already cutting down on the emissions tallied by the government. Spokesmen for the Independent Petroleum Association of America and the natural gas lobbying groups Energy in Depth, American Clean Skies Foundation and America's Natural Gas Alliance, which have all been pushing to expand the use of gas, declined to comment on the EPA's new figures and what they mean for the comparison between gas and coal.
But industry groups point out that gas looks attractive compared to the alternatives.
Nuclear energy is less polluting than gas from a climate-changing perspective, but it is costly and viewed skeptically in the United States because of the dangers of disposing of radioactive waste. So-called "clean coal"—including underground carbon sequestration—could work, but the technology has repeatedly stalled, remains unproven, and is at least 15 years away. Renewable sources like wind and solar are being developed rapidly, but the energy is expensive and won't provide a commanding supply of electricity for decades.
Gas, on the other hand, is plentiful, accessible and local.
Methane Is a Potent Climate Gas
Measuring the amount of natural gas that is leaking during drilling is one challenge. Getting a grip on how that gas—which is mostly methane—affects the environment, and what effect it will have on global warming, is another. And on that, some scientists still disagree.
Greenhouse gases include carbon dioxide, as well as methane, propane and lesser-known gases that also affect climate change. For the purposes of standardization, all these gases are described together using the unit Co2e, or carbon dioxide "equivalent." But because each gas has a different potency, or "warming" effect on the atmosphere, a factor is applied to convert it to an equivalent of carbon dioxide.