Debunking The Myth: Hydrogen Is Not A Zero Emissions Fuel

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Last Updated on: 19th March 2025, 05:58 pm

The idea that hydrogen is a “zero-emissions” energy source is one of those claims that sounds great in a press release but crumbles under scrutiny. Sure, when you burn hydrogen or use it in a fuel cell, there’s no CO₂ spewing out the tailpipe. That much is true. But this claim is a classic example of a cherry-picking fallacy — focusing on the most flattering detail while sweeping inconvenient realities under the rug.

This is a companion article to the Cranky Stepdad vs Hydrogen for Energy material. In a similar manner to John Cook’s Skeptical Science, the intent is a rapid and catchy debunk, a second level of detail in the Companion to Cranky Stepdad vs Hydrogen for Energy, and then a fuller article as the third level of detail.

Hydrogen’s zero-emissions claim is like calling a sieve full — emissions still leak through at every stage.

Over 95% of hydrogen today is produced using fossil fuels, primarily through steam methane reforming (SMR). This process involves reacting natural gas (methane) with steam to produce hydrogen — and, inconveniently, a whole lot of carbon dioxide (Howarth & Jacobson, 2021). Even so-called “blue hydrogen,” which attempts to capture some of those emissions, still results in substantial CO₂ leakage across its lifecycle (Ocko & Hamburg, 2022). The only truly low-carbon option — electrolysis powered by renewable energy — remains a tiny fraction of global hydrogen production because it’s expensive and energy-intensive.

Even if we magically switch to 100% “green” hydrogen tomorrow, there’s still a fundamental problem: hydrogen leaks. And when it leaks, it doesn’t just vanish into the ether — it messes with the climate. Hydrogen has a global warming potential (GWP) of 37 over 20 years and 12 over 100 years (UK Department for Environment, Food & Rural Affairs [DEFRA], 2022). That means that even small leaks — whether from production, storage, or transportation — act as indirect climate forcers, prolonging the atmospheric lifetime of methane and increasing ozone levels (Derwent et al., 2020). The industry acknowledges leakage rates over 1% per stage, which adds up quickly in real-world applications (International Energy Agency [IEA], 2023). The more hydrogen we move around, the bigger this problem becomes.

Let’s not forget that when hydrogen is combusted — whether in a turbine, a boiler, or an internal combustion engine — it produces nitrogen oxides (NOx), potent air pollutants linked to respiratory diseases and smog formation (U.S. Department of Energy [DOE], 2023). That’s why burning hydrogen in a power plant or vehicle doesn’t magically make it “clean.” If your climate plan involves swapping out natural gas for hydrogen and then burning it, congratulations — you’ve just invented an expensive way to keep making air pollution.

So, where does that leave us? Hydrogen is not a zero-emissions energy source, no matter how you spin it. The production process is carbon-intensive, the leakage accelerates global warming, and combustion still pollutes. That doesn’t mean hydrogen has no role to play as it’s essential as an industrial feedstock for ammonia, among other critical chemicals—but it does mean we should stop pretending it’s a silver bullet for decarbonization (Bloomberg New Energy Finance [BNEF], 2023). If we’re serious about net zero, we need to focus on real zero-carbon solutions, not marketing gimmicks dressed up as climate strategy.

References:

Bloomberg New Energy Finance (BNEF). (2023). Hydrogen’s hidden emissions: Leakage, NOx, and upstream carbon costs.

Derwent, R. G., Simmonds, P. G., Manning, A. J., & Spain, T. G. (2020). Global environmental impacts of hydrogen leakage. International Journal of Hydrogen Energy, 45(7), 3875–3893.

Howarth, R. W., & Jacobson, M. Z. (2021). How green is blue hydrogen? Energy Science & Engineering, 9(10), 1676–1687.

International Energy Agency (IEA). (2023). The role of hydrogen in decarbonization: Addressing climate and emissions challenges. Paris: IEA.

Ocko, I. B., & Hamburg, S. P. (2022). Climate consequences of hydrogen emissions. Atmospheric Chemistry and Physics, 22(12), 9349–9368.

UK Department for Environment, Food & Rural Affairs (DEFRA). (2022). Atmospheric impacts of hydrogen: Indirect greenhouse gas effects.

U.S. Department of Energy (DOE). (2023). Hydrogen emissions and lifecycle carbon footprint analysis. Washington, DC: DOE.