Producing “blue” hydrogen from natural gas and adding carbon capture to the process carries a 20% higher greenhouse gas footprint than just burning gas or coal for heat, two eminent U.S. researchers conclude in a new paper in the journal Energy Science & Engineering.
Blue hydrogen has been heavily hyped in Canada and around the world, and derided as greenwashing, as a way to decarbonize fossil fuel production by capturing and storing carbon dioxide emissions. The new study by Robert Howarth of Cornell University and Mark Z. Jacobson of Stanford University focuses in on methane—a greenhouse gas that is about 80 times more potent than CO2 over a 20-year span, a known source of emissions from fracked gas operations, and chronically unmeasured and under-reported.
“Far from being low-carbon, greenhouse gas emissions from the production of blue hydrogen are quite high, particularly due to the release of fugitive methane,” Howarth and Jacobson write. Total emissions of CO2 and equivalent are only 9 to 12% lower than for “grey” hydrogen—the variety produced from gas or coal with no carbon capture. And “while carbon dioxide emissions are lower, fugitive methane emissions for blue hydrogen are higher than for grey hydrogen because of an increased use of natural gas to power the carbon capture.”
The net result: assuming a 3.5% emissions rate for methane, “the greenhouse gas footprint of blue hydrogen is more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat.” Even with methane emissions brought down to 1.5%, the resulting emissions are “still greater than from simply burning natural gas, and are only 18 to 25% less than for grey hydrogen.”
The analysis also takes at face value the industry’s promise that captured carbon can be stored indefinitely, even though Howarth and Jacobson describe that assumption as “optimistic and unproven”. Even if it’s true, they say, “the use of blue hydrogen appears difficult to justify on climate grounds”.
One of the biggest takeaways from last week’s blockbuster science report from the Intergovernmental Panel on Climate Change was that reducing runaway methane emissions from shale gas, oil extraction, and animal farming will be a cornerstone of any effort to get the climate crisis under control. “One of the key action points for policy-makers is likely to be a warning that methane is playing an ever greater role in overheating the planet,” The Guardian reported.
“Cutting methane is the biggest opportunity to slow warming between now and 2040,” said Durwood Zaelke, president of the Institute for Governance and Sustainable Development and a lead IPCC reviewer. “We need to face this emergency.”
Beyond the issue with methane, the two authors note that “several non-peer-reviewed reports” promise carbon dioxide capture rates of 56 to 90% for blue hydrogen, depending on the technology a company uses. “However, no data have been presented to support these estimates, and they apparently do not include emissions associated with the energy needed to drive carbon capture,” they write. “Our results using a full life-cycle assessment show [the] assumptions are too optimistic.”
In a separate technical paper published last week, the Pembina Institute lists carbon capture rates of 29 to 43% for existing blue hydrogen projects in Alberta, Oklahoma, and Texas. The chart also shows two projects with “proposed” capture rates of 95% using the newer auto-thermal reforming (ATR) capture process—but their performance can’t be verified, since they won’t go into operation until 2024 or 2026.
Earlier this year, an industry observer said U.S. and potential Canadian tax credits for carbon capture could give plant operators an incentive to extract more fossil fuels.
“You now have a plant that has two products,” David Schlissel, director of resource planning at the Institute for Energy Economics and Financial Analysis, told The Energy Mix. “The more CO2 they produce, the more they can capture, and the higher their revenues are, so they have an incentive to run the plants more to capture more CO2. All in the name of reducing our CO2 emissions in order to help stave off climate change.”
“You could be nice and say this is a perverse incentive,” he added. “But when I’m alone, I just say it’s insane.”
Read the detailed analysis by Robert Howarth and Mark Z. Jacobson here.