Given the shale boom, the United States has now become the world's leading natural gas producer. Because it only releases 50% as much emissions for the same equivalent amount of energy produced by oil or coal, many have herald it as a cleaner source of fossil energy, whose widespread introduction might help mitigate global warming. A new study found that in the long run, natural gas does little to curb emissions since it would boost consumption (high supply means it will be cheaper) and displace renewable energy.
Natural gas: a poor strategy for mitigating global warming
Researchers at the UC Irvine, Stanford Univ. and the nonprofit organization Near Zero estimated the natural gas supply curves for the next 40 years, then modeled the the effect of varying natural gas supplies on the U.S. electricity mix, as well as the resulting greenhouse gas emissions under four scenarios: no policy, a moderate carbon tax, a stringent cap on emissions, and a requirement of 50% renewable electricity by 2050.
Most of the energy in the US comes coal-fired plants and the U.S. Environmental Protection Agency (EPA) recently proposed a plan to substitute coal with natural gas 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,” says lead author Christine Shearer, a postdoctoral scholar in Earth system science at UC Irvine.
The study also took into account that 1.5 percent of the gas would be lost during production and transport of the fuel, yet even if there were no methane leaks, as opposed to reality, the overall climate benefits of gas are likely to be small since it would discourage renewable energy projects. The only scenario examined in the study, which favored renewable energy under all conditions, was the 50 percent renewable energy mandate by 2050.
All in all, the researchers who described their findings in the journal Environmental Research Letters state that relying on natural gas is a poor strategy for cleaning the environment with risks of backfiring.
"Cutting greenhouse gas emissions by burning natural gas is like dieting by eating reduced-fat cookies. It may be better than eating full-fat cookies, but if you really want to lose weight, you probably need to avoid cookies altogether," Steven Davis, assistant professor of Earth system science at UC Irvine, said.