Blue Hydrogen Study Finds It Isn't Climate-Friendly, Igniting Fierce Debate Over Emissions

A recent study casts doubt on the green credentials of so-called “blue hydrogen” and it has caused a stir in the scientific community.

Government Announces National Hydrogen Strategy
Sean Gallup / Getty Images

Blue hydrogen, a purportedly green fuel that is typically extracted from natural gas, has long been touted as a climate solution but a controversial peer-reviewed study released last week argues its production is linked to high greenhouse gas emissions. 

Robert Howarth, a professor of ecology and environmental biology at Cornell University, and Mark Jacobson, a professor of civil and environmental engineering at Stanford, say that when compared to burning coal and natural gas to produce heat, blue hydrogen produces 20% more emissions.

Hydrogen itself is considered a clean fuel because it can be used to produce energy or heat without releasing greenhouse gases into the atmosphere, other than water vapor. Many researchers have long argued that blue hydrogen should play a role in the decarbonization of global energy systems because it can potentially be used to power all kinds of vehicles and generate electricity. 

The International Energy Agency (IEA), for example, argues that in order to slash energy emissions, hydrogen should account for around 13% of global energy demand by 2050. The Biden administration, the European Union, and the United Kingdom back blue hydrogen to various degrees.

On top of that, blue hydrogen has also been promoted by fossil fuel companies, including ExxonMobil and BP, which see it as a new revenue source. 

However, the production of blue hydrogen from natural gas is anything but clean, the study argues.

"Political forces may not have caught up with the science yet," said Howarth. "Even progressive politicians may not understand for what they're voting. Blue hydrogen sounds good, sounds modern, and sounds like a path to our energy future. It is not.”

The production of blue hydrogen is energy-intensive. It requires natural gas to be extracted and transported. The methane from the gas is subjected to steam, heat, and pressure to produce hydrogen, a process that creates carbon dioxide as a waste product. To make that hydrogen “blue” (as opposed to “gray" hydrogen, which has a much higher carbon footprint) the resulting carbon dioxide has to be captured and stored to ensure that it does not end up in the atmosphere.

The main reason why blue hydrogen has a very carbon footprint, the study argues, is natural gas production is responsible for high methane emissions, a greenhouse gas that is more than 80 times more potent than carbon dioxide when it comes to trapping heat in the atmosphere over a 20-year period. 

“Further, our analysis does not consider the energy cost and associated greenhouse gas emissions from transporting and storing the captured carbon dioxide. Even without these considerations, though, blue hydrogen has large climatic consequences. We see no way that blue hydrogen can be considered ‘green.’” 

Scientific Controversy

Some researchers argue the “How green is blue hydrogen?” study is flawed because the authors assumed that about 3.5% of the methane that is extracted is leaked into the atmosphere.

Jilles van den Beukel, an energy analyst based in the Netherlands, tells Treehugger that other estimates put the leakage figure at between 1.4% and 2.3%—although he noted that there are also higher estimates.

In addition, Van den Beukel says if the study authors had analyzed emissions over a 100 year period instead of a 20 year period, they would have found blue hydrogen is more climate-friendly.

He argues that “you can certainly reduce the carbon footprint of blue hydrogen; whether that is sufficient to make it an attractive option that deserves support is another matter.”

Van den Beukel says strong regulations and high technical standards in North Sea natural gas fields lead to very low methane emissions.

“The real question is: can you also achieve a similar level in the U.S.? For shale gas, with low production volumes per well, it will be more difficult to achieve similar low emissions. But it can certainly be a lot lower than what it is today,” he adds.

Still, Van den Beukel argues “low carbon hydrogen” should play a role in a decarbonized future “for the applications that are difficult to electrify, such as long and medium-distance aviation and shipping, industrial heat, steel production.”

While a heated debate over the claims of the study raged online, with some claiming that the study authors “cherry-picked” their data to make hydrogen “look bad,” while others said the research exposed some hard truths about hydrogen production, the head of the U.K.'s hydrogen industry association, Christopher Jackson, resigned saying he was convinced that blue hydrogen was the wrong answer to climate change.

Jackson said: “In 30 years’ time, everyone working in the energy sector today will be asked by the generations that follow us, what we did to prevent the coming climate catastrophe. And I believe passionately that I would be betraying future generations by remaining silent on that fact that blue hydrogen is at best an expensive distraction, and at worst a lock-in for continued fossil fuel use that guarantees we will fail to meet our decarbonization goals.”

Underestimated Methane Emissions

To a large extent, the debate centers on how to estimate methane emissions from the fossil fuel industry, which is responsible for about one-fourth of the methane that is leaked into the atmosphere every year.

According to research by the IEA, fossil fuel companies emitted 70 million metric tons of methane into the atmosphere last year alone.

“Assuming that one metric ton of methane is equivalent to 30 metric tons of carbon dioxide, these methane emissions are comparable to the total energy-related carbon dioxide emissions of the European Union,” the IEA said.

The IEA estimates that in order to prevent the worst effects of climate change, the world would need to slash methane emissions by 70% over the next decade and the United Nations describes methane as “the strongest lever we have to slow climate change over the next 25 years” in large part because cutting methane emissions should be more straight forward than reducing carbon dioxide emissions.

However, experts have long argued that methane emissions from the fossil fuel industry are probably underestimated. A study by the Environmental Defense Fund found that actual methane emissions from fossil fuel operations between 2012 and 2018 were 60% higher than what the EPA estimated — a peer-reviewed paper released earlier this year also found that methane emissions from fossil fuel companies were higher than previously thought.

On Wednesday, co-founder Bill McKibben chipped into the blue hydrogen debate arguing in an article for The New Yorker that blue hydrogen will likely lead to more methane emissions. He writes:

“The first way to reduce methane in the atmosphere, of course, is to stop building anything new that’s connected to gas: stop installing gas cooktops and gas furnaces, and substitute electrical appliances. And stop building new gas-fired power plants, instead substituting sun, wind, and battery power. And, as a really important new study by the star energy academics Bob Howarth and Mark Jacobson emphasizes, by all means, do not start using natural gas to produce hydrogen, even if you’re capturing the carbon emissions from the process.”
View Article Sources
  1. Howarth, Robert W., and Mark Z. Jacobson. "How Green is Blue Hydrogen?" Energy Science & Engineering, 2021, doi:10.1002/ese3.956

  2. "Hydrogen Fuel Basics." Office of Energy Efficiency and Renewable Energy.

  3. "Net Zero by 2050." International Energy Agency, 2021.

  4. "Importance of Methane." United States Environmental Protection Agency.

  5. "Global Methane Emissions and Mitigation Opportunities." Global Methane Initiative.

  6. "Methane Tracker 2021." International Energy Agency.

  7. "Global Assessment: Urgent Steps Must be Taken to Reduce Methane Emissions this Decade." United Nations, 2021.

  8. "Maasakkers, Joannes D., et al. "2010–2015 North American Methane Emissions, Sectoral Contributions, and Trends: A High-Resolution Inversion of GOSAT Observations of Atmospheric Methane." Atmospheric Chemistry and Physics, vol. 21, no. 6, 2021, pp. 4339-4356., doi:10.5194/acp-21-4339-2021

  9. "Major Studies Reveal 60% More Methane Emissions." Environmental Defense Fund.