Implications of Generation Efficiencies and Supply Chain Leaks for the Life Cycle Greenhouse Gas Emissions of Natural Gas-Fired Electricity in the United States

Abstract

Uncertainties in supply chain emissions raise questions about the benefits of natural gas as a bridge fuel, but recent efficiency improvements in gas-fired electricity generation remain overlooked. Our comprehensive analysis of supply chain infrastructure and electricity generation across the United States informs spatially and temporally resolved estimates of life cycle greenhouse gas emissions. Results show decreasing life cycle emissions over each year examined: 629, 574, and 525 kg CO2 eq MWh–1 in 2005, 2010, and 2015, respectively. Electricity generation contributed 86% of emissions or greater for each year. Despite concerns over uncertain methane leaks, efficiency improvements make it much more likely that natural gas electricity has an unambiguous greenhouse gas benefit relative to coal. Methane leaks would have to be 4.4 times the Environmental Protection Agency (EPA) value in 2015 to reverse these benefits over 20-year time horizons. With retiring coal plants and scrutinized supply chain emissions, our results show that natural gas can provide a lower emissions option to coal in an increasingly decarbonized power sector.

Air pollution and health impacts of oil & gas production in the United States

“…The U.S. Environmental Protection Agency (U.S. EPA) estimates indicate that natural gas and petroleum production and transportation systems are the second largest emitters of methane-emitting 7.05 million metric tons in 2018 [1][2][3][4][5][6]. Research on 2015 emissions indicates this may be underestimated by ∼60% [1].…”

“…While methane emissions across the life cycle of oil and gas have been a topic of a large body of previous research [1,4,[15][16][17][18][19][20][21], comparatively few studies have focused on fully quantifying the health and air pollution impacts of oil & gas production in the U.S [22,23]. These health costs could be an important component of the full life cycle costs of oil and gas, and an important consideration in the design of policies around emissions from O&G production.…”

A Modified Gaussian Plume Model for Mobile in situ Greenhouse Gas Measurements

“…Methane has a global warming potential that is 28 times that of CO 2 over a 100 year period, and is a valuable energy resource (IPCC, 2013). In the atmospheric carbon cycle, methane eventually reacts to form CO 2 , so mitigating emissions by flaring, or fuel use is less harmful than allowing direct emissions of methane to the atmosphere (Kirschbaum, 2014;Tavakkoli et al, 2022). In the urban environment, when compared to the nearly-ubiquitous emissions of CO 2 , there is a relatively small number of highly emitting facilities and point sources of CH 4 , making it a good candidate for mobile survey measurement strategies.…”