There is no question that gas extraction, production, and use is a significant contributor to our climate crisis, but just how bad it is depends a lot on how much the gas system leaks. This is because it emits methane, which is a very potent greenhouse gas — contributing more than 80 times the warming potential of carbon dioxide over a 20-year period. The Gas Index, just released by Climate Nexus and developed by Global Energy Monitor, uses the newest methane science to estimate leakage from the wellhead to the home, and presents lifecycle leakage rates for 71 cities across the United States — showing rates far higher than the government’s estimates.
The gas problem
The production, transportation, and combustion of fossil (aka “natural) gas poses a myriad of problems for clean air, clean water, wildlife, landscapes and ecosystems, human health, local communities, and our climate. Leaking gas infrastructure is a source of unaddressed climate and other harmful air pollution and can create emissions hotspots, significant public human health impacts, and environmental justice issues because it is often located in, or cuts across, disadvantaged areas.
Unfortunately, gas use is growing — primarily due to power plants using more of it and continued construction of new buildings heated with gas. Gas was the only fuel source to see increased carbon pollution in 2019 (while economy-wide emissions fell 3 percent). When it is burned, gas typically emits half the carbon of coal, so one might conclude that gas can help us reduce emissions (and many have). But there are problems with that reasoning.
First, with efficiency and renewable energy far cheaper and more abundant than coal, the choice is no longer between coal and gas. Likewise, there are much more efficient and cleaner electric appliance and equipment alternatives to direct use of gas in buildings (for example, electric heat pump water heaters are up to 5 times more efficient than conventional gas water heaters), which are a key part of the long term solution to equitable building “decarbonization” for all households.
Second, that comparison of gas to coal does not count the methane leaked all along the gas supply chain. And as the new analysis by Global Energy Monitor shows, that amount is much higher than we thought.
Inside the new Gas Index
The analysis found that all 71 cities evaluated had lifecycle methane emission rates higher than estimated in the U.S. Environmental Protection Agency’s Greenhouse Gas Emissions (GHG) Inventory — some more than four times higher. Global Energy Monitor relied on newer and more comprehensive studies across the gas system in its analysis. For example, the analysts included measurements from oil and gas production areas responsible for 90 percent of production versus only one-third from older studies that showed slightly higher leakage rates than EPA estimates.
Even more notably, new measurements of leakage within cities found much higher rates than EPA estimates from local gas distribution pipelines (nearly 5 times as much); leaks from customers’ gas meters (up to 6 times higher); and from behind the meter leakage (from pipes and appliances like tankless gas water heaters within buildings), which EPA’s GHG Inventory doesn’t even include. Other researchers’ measurements of citywide emissions from gas, using flights overhead and measurements from towers located in and around the cities, show there is also leakage even greater than the sum of the individual supply components (see graphic above) estimated by Global Energy Monitor. Its analysis was careful to weed out emissions from non-fossil gas sources like landfills, but these “additional,” or unaccounted for emissions could be from gas distribution pipelines, customer gas meters, and/or behind-the meter leakage — we just don’t know.
What this means for cities & states
Eliminating emissions in America’s buildings is a crucial component to meeting our carbon reduction goals, given that they are responsible for 40 percent of our carbon emissions — and up to 75 percent of a city’s emissions. It is also fundamental to making cities more healthy, equitable, and affordable places to live.
The Index presents the most up to date and best available estimates of the leakage rate of each of the 71 cities’ gas supply. This is critical new information for the many cities that have established, or are considering, aggressive carbon reduction strategies. Meeting these commitments will require massive amounts of increased energy efficiency for all homes, electrifying buildings, and ensuring the energy to power, heat, and cool buildings comes from renewable, zero-carbon energy sources. The Gas Index could make the carbon math even more favorable than it already is for equitably transitioning households from gas appliances and equipment burning gas on site to highly efficient electric appliances.
The largest use of gas in U.S. buildings is for space heating. Studies by Rocky Mountain Institute and Sierra Club already show that switching from gas to electric heating would cut emissions in all 50 states. This new study further increases the climate benefits of transitioning away from gas in buildings. And this doesn’t even account for the economic, public health, and other environmental impacts to customers and cities as gas infrastructure investments become stranded. The move away from gas must begin with prioritizing Black, brown, and Indigenous communities, and low-income households, who are most at risk from an unmanaged transition. Decision-makers should review this report carefully as they consider new proposals by gas distribution utilities to invest billions in pipe replacement, or in building out new pieces of the gas distribution system.
A recent report noted that while global carbon emissions will be down 7 percent this year due to the pandemic, we still need to cut climate pollution more than 7 percent per year through 2030 to even hope to stay below a 1.5 degrees Celsius rise in global temperatures. Our new federal administration must reverse the rollbacks of protections intended to curb methane emissions, and mandate that leaks from oil and gas wells, pipelines, and other facilities be located and stopped. But it is our American cities that can and must lead in the transition away from our dependence on gas to improve the health and equity for their residents and combat this climate crisis. The fact that so many cities already get it, gives me great hope.
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