Report: “Renewable” Gas – A Pipe Dream or Climate Solution?

The gas industry is scrambling to claim “renewable” alternatives to fossil gas will allow us to continue depending heavily on appliances that burn gas and investing in new pipelines to transport it while still meeting our climate goals. A new NRDC Issue Brief shows this simply isn’t true. While cleaner gas alternatives to natural gas (more accurately described as “fossil gas”) exist, they could only sustainably replace around 3 to 7 percent of today’s gas use, cost much more, and don’t avoid the damage to human health from burning gas.

Workers inspect an anaerobic digestion solid waste processing facility that converts food and green organic waste into biogas.

Credit: Billy Hustace/Getty Images

It’s important to dig into the opportunities and limitations of alternatives to fossil gas so that we understand what these resources might able to provide—and aren’t lulled into assuming they can take care of America’s “gas problem.” The use of gas is growing, particularly to generate electricity. But reducing the greenhouse gas (GHG) emissions driving the climate crisis requires replacing highly polluting fossil fuels like gas with low-carbon or zero-carbon energy resources. This is understandably a serious concern for the gas industry, and to any gas utility not planning for a strategic phaseout of fossil gas demand.

“A Pipe Dream or Climate Solution? The Opportunities and Limits of Biogas and Synthetic Gas to Replace Fossil Gas” examines the potential for the two types of gas that some term “renewable”—biogas and synthetic gas—to displace fossil gas:

  • Biogas is primarily methane produced from organic sources such as food scraps, animal waste, or woody biomass. The biogas resources are limited in supply, often have significant environmental consequences. Many also have more beneficial uses than being converted to methane.
  • Synthetic gas is methane or hydrogen created using electrical power. Synthetic gas has some potential to scale with the growing supply of renewable electricity, but synthetic methane (the focus of this issue brief) is still projected to be very expensive in 2040 and 2050.

According to a study sponsored by the American Gas Foundation (AGF) and conducted by ICF International, the United States could produce 1,660 to 3,820 TBtus (trillion Btus) of biogas and synthetic gas annually by 2040 (this is 5 to 12 percent of last year’s total U.S. gas use). On the basis of these numbers, NRDC applied its own screens to project that biogas and synthetic gas could sustainably replace roughly 3 to 7 percent of the country’s 2019 gas use, with biogas replacing 2 to 5 percent and synthetic methane replacing 1 to 2 percent. While those contributions would help, they do not justify reliance on biogas and synthetic gas as a primary strategy to replace fossil gas use.

The figure below shows the AGF study’s low and high estimates of potential biogas and synthetic gas supply by 2040, along with NRDC’s estimates of sustainable gas potential.

Biogas and synthetic gas should be used sparingly and strategically. First, to meet gas and electricity needs at the site where the gas is generated, which avoids transporting methane and building new pipelines. And then to reduce emissions from activities that are most difficult to power with renewable electricity, such as industrial processes, aviation, long-distance transportation, and electricity generation to balance seasonal fluctuations in wind and solar resources.

Given the nascent state of this market, policies that aim to replace fossil gas with biogas and synthetic gas should start small and grow only if the resource proves to be available, economical, and environmentally sound. In addition, these policies must include environmental requirements to screen the resources used, and differentiate among them through active monitoring and reporting of life-cycle carbon dioxide and methane emissions, accounting for both short-term and long-term climate impacts.

Given the need to substitute emissions-free clean energy for polluting fossil gas in all sectors to meet climate goals, and the limited supply of biogas and synthetic gas, electricity from abundant renewable resources like wind and solar will be the fuel of choice in most sectors. Overall gas use and investment in gas infrastructure will need to decline to meet both climate and air quality goals. States urgently need to begin planning for a smaller gas footprint to avoid saddling a dwindling number of gas customers with rising gas bills from sprawling, but increasingly underused, gas infrastructure.

Special thanks to Olivia Ashmoore, former NRDC intern, for conducting extensive research into biogas and synthetic gas resources to inform the development of this blog and NRDC’s new Issue Brief.

About the Authors

Merrian Borgeson

Senior Scientist, Climate & Clean Energy Program

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