Absent climate policies, widespread use of natural gas is unlikely to curb greenhouse gases — study

Source: Stephanie Paige Ogburn, E&E reporter • Posted: Monday, May 19, 2014

An oft-heard comment about America’s natural gas boom is that it has led to a reduction of greenhouse gas emissions. Insofar as natural gas replaces coal in electricity generation, this claim is probably true.

But step back and look globally and into the future, and widespread use of natural gas fails to significantly alter the world’s current global warming trajectory, a new study finds.”In the absence of [emissions reduction policies] there’s no guarantee that natural gas will reduce greenhouse gas emissions,” said Richard Newell, a Duke University researcher and expert in environmental economics who led the study, which was published recently in the journal Environmental Science & Technology.

“What we find is that simply left to the market, it seems that natural gas will neither significantly increase nor significantly decrease greenhouse gas emissions,” Newell added.

Newell’s study sprang out of a National Academy of Sciences workshop on the environmental implications of shale gas development, he said. While there has been a significant amount of research recently looking into the question of how much methane, a powerful greenhouse gas, is emitted by the natural gas sector, Newell found that a synthesis of its overall climate change effects had not yet been completed.

Natural gas prices are currently low because it is abundant in the United States. This has led to the fuel’s being substituted for coal, which has positive greenhouse gas outcomes, according to most research. This replacement of natural gas for coal is likely to continue, according to the study.

But as time goes on, if cheap, abundant natural gas leads it to outcompete more zero-carbon sources than it does coal and oil, that would have a negative outcome for carbon dioxide emissions, the study finds.

If natural gas outcompetes renewables, the climate loses

Right now, the main competition in electric power investment has been and looks like it will be between natural gas and wind,” Newell said.

Policies that encourage emissions reductions might tilt the balance toward renewables. But absent those policies, the cheaper option, not necessarily the most climate beneficial, wins out.

It’s not that natural gas can’t have climate benefits. But “whether that occurs is going to depend in significant part in the policy context into which natural gas enters,” Newell said.

Newell’s paper spends some time discussing leaks of methane during the natural gas production process, and his review of the literature finds that many papers have found emissions are likely higher than current U.S. EPA estimates, and more work is needed to explain the divergence between studies with findings in line with EPA estimates and those finding higher rates of emissions.

Yet while methane leaks are a problem and undercut the climate advantage that natural gas has with regard to coal, few researchers would say the leakage is so high as to make natural gas worse for the climate than coal.

Yet if natural gas replaces diesel fuel in trucking, for example, unless it leaks less than 0.8 percent, it will have a deleterious effect on climate change.

If the natural gas boom expands outside the United States and production also explodes globally, the same substitutions of gas for coal are likely to occur, but the problems of methane leakage and the potential for natural gas to outcompete renewables also persist, the study states.

Better LNG use policies needed to reduce emissions

Michael Obeiter, a senior associate in the Climate and Energy Program at the World Resources Institute, said there is a need for climate policy that takes advantage of the potential benefits of natural gas.

“Overall, so far, natural gas has reduced greenhouse gas emissions, but going forward, there are a lot of policies that need to be put in place to ensure natural gas continues to drive greenhouse gas reductions,” Obeiter said.

The best policy would be one that puts a price on carbon, Obeiter said. Absent that, he said, the EPA rules for power plants can be an effective means of encouraging lower emissions.

Obeiter praised recent regulations in Colorado to limit methane leaks from oil and gas production sites.

Although the EPA rules on existing natural gas power plants currently are not stringent enough to require that most plants curtail their emissions, the agency needs to indicate that emissions limits will be ratcheted down over time, Obeiter said.

The push to export liquefied natural gas could also result in further reductions to the climate benefit of using natural gas, as it is an energy-intensive process with the potential for leaks.

According to recent testimony by WRI’s James Bradbury in front of the House Energy and Commerce Committee, LNG export increases the total greenhouse gas emissions of natural gas by 15 percent compared with gas reduced domestically.

In its conclusion, the study states that the real solution to reducing global greenhouse gas emissions lies in pursuing energy options with low amounts of greenhouse gases like nuclear, renewables, and carbon capture and storage, possibly fueled by cheap and abundant natural gas.

The study also called for increased research into changes in international trade patterns due to shale gas growth and the emissions comparisons of natural gas versus electric- and oil-based heating systems.