Get the Latest on the Gas Index - a Ranking of City Gas Supply Leaks
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Press release, Dec. 15, 2020


New Analysis Reveals Extensive Methane Leakage Coming from City Gas Supplies


The Gas Index ranks and analyzes gas supply leaks from wellhead to home


Austin, TX – The Gas Index, a new report and website published today by Global Energy Monitor, offers a first-of-its-kind look at methane leakage attributable to natural gas use in 71 cities across the U.S.


The Gas Index ranks cities by how leaky their gas supplies are, based on a model that evaluates where each state’s gas supplies come from, and how much leakage occurs in each city. Natural gas is mostly composed of methane, a greenhouse gas with a much more powerful  warming effect than carbon dioxide, so gas leakage significantly increases the climate impacts from burning gas in homes and businesses.


“For the U.S. to sharply cut its greenhouse gas emissions, every part of the economy and every city needs to do its part,” said Mason Inman, Program Director for Gas at Global Energy Monitor and the leader of the Gas Index project. “Our results show that gas is leaking throughout the system, with significant differences between cities in how large the emissions are, and where the emissions are coming from. Our city-by-city results highlight where efforts to fix the gas system can be most effective—and also highlights how cities can achieve large emissions cuts by switching homes and other buildings from using gas to using electricity.”


The Gas Index model incorporates data from dozens of studies that have measured methane leakage in oil and gas extraction areas, along gas transmission pipelines, and within cities—including inside homes and businesses. In this way, the model evaluates the full life cycle to estimate a gas leakage rate for each city’s gas supply.


The Gas Index draws on new research showing that the Environmental Protection Agency is substantially underestimating methane leakage. On average across all sectors, the Gas Index calculates the methane leakage rate is 72% higher than the EPA value. More leakage occurs in delivering gas to residential and commercial customers, so the Gas Index calculates leakage rates for gas supplied to these sectors is more than double than the EPA value.


The report also estimates emissions reductions for electrification of residential and commercial heating in the cities analyzed, showing where building electrification to reduce reliance on gas can have a major impact. In all cities analyzed, switching from gas heating to efficient electric heat pumps produces emissions savings.


The ten cities with the leakiest gas supplies are Indianapolis, Ind.; Los Angeles, Calif.; Phoenix, Ariz.; Miami, Fla.; Oklahoma City, Okla.; Orlando, Fla.; Boston, Mass.; Little Rock, Ark.; Reno, Nev.; and Tampa, Fla. The analysis shows and compares contributions to leakage from different parts of the gas system, such as gas production areas or pipelines within cities. The city with the leakiest gas supply—Indianapolis—has a leakage rate more than four times higher than the EPA’s estimated national average.

The U.S. Natural Gas System Has a Serious Problem: The Gas Leaks.

“We think about natural gas as being a single, standardized fuel with a single environmental profile, when that’s not the case. The Gas Index really highlights that it’s true in general that methane leakage is a significant problem for climate intensity of gas, and that some places have more urgent challenges in this area,” said Dr. Emily Grubert, Assistant Professor of Civil and Environmental Engineering at Georgia Tech, and an adviser to the Gas Index.


“By examining leakage across the natural gas supply chain and utilizing the most recent scientific findings, The Gas Index provides holistic and current estimates of methane emissions across several urban areas. The Gas Index and similar inventories are crucial for understanding where and how investments in infrastructure and electrification will result in economic and meaningful reductions in greenhouse gas emissions,” said Dr. Zachary Weller, Assistant Professor of Statistics at Colorado State University, and an adviser to the Gas Index.