Replacing coal with natural gas to produce electricity wouldn’t significantly reduce carbon emissions, according to a study released today, by the University of California Irvine in conjunction with Near Zero and Stanford University.
President Obama, among others, has pushed natural gas as a “bridge fuel” that could help countries lower greenhouse gas emissions while making the slow transition to renewable energy. UC Irvine’s study refutes that, instead finding that inexpensive gas boosts electricity consumption and hinders the expansion of cleaner energy sources such as wind and solar.
The study results, which appeared today in the journal Environmental Research Letters, are based on modeling the effect of high and low gas supplies on the U.S. power sector.
Coal-fired plants, the nation’s largest source of power, also produce vast quantities of carbon dioxide, the main greenhouse gas polluting the Earth’s atmosphere. Recently proposed rules by the U.S. Environmental Protection Agency rely heavily on the substitution of natural gas for coal to lower carbon emissions by 2030.
“In our results, abundant natural gas does not significantly lower greenhouse gas emissions. This is true even if no methane leaks during production and shipping,” said lead author Christine Shearer, a postdoctoral scholar in Earth system science at UC Irvine.
Natural gas is composed mainly of methane, which is a greenhouse gas in itself. While burning natural gas produces only half the greenhouse gas emissions as coal, if large quantities are leaked–from old pipelines, for example–it’s just as harmful to the environment. But in this study, reducing methane leaks to zero didn’t make much of a difference. What really made a difference in carbon emissions were the policies used to regulate production and consumption.
“Natural gas has been presented as a bridge to a low-carbon future, but what we see is that it’s actually a major detour. We find that the only effective paths to reducing greenhouse gases are a regulatory cap or a carbon tax,” Shearer said.
She further explains the finding in a video abstract of the study.
As Shearer explains, one of the main issues is that natural gas would not only be competing with coal, but with renewable sources of energy. This would slow down the progress of wind and solar powered energy.
“Cutting greenhouse gas emissions by burning natural gas is like dieting by eating reduced-fat cookies,” said Steven Davis, assistant professor of Earth system science at UC Irvine and the study’s principal investigator. “It may be better than eating full-fat cookies, but if you really want to lose weight, you probably need to avoid cookies altogether.”
- Read the full study published by Environmental Research Letters.