Assertion: Very low levels of hydrogen leakage are acceptable and will not undermine hydrogen decarbonization goals relative to alternative solutions

The effectiveness of hydrogen as a decarbonization tool depends on its leakage rate, as higher rates diminish its ability to prevent warming due to indirect warming effects. However, research shows that green hydrogen remains beneficial for the climate even with leakage rates as high as 10%. For instance, a 2022 study in the Journal of Atmospheric Chemistry and Physics found that green hydrogen projects with a 10% leakage rate can still reduce the warming potential of continuing to use fossil fuels by 60% in ten years.¹ In contrast, projects with a 1% leakage rate, the low end of most estimates, can reduce warming potential by over 90%.²

A 2024 study from the Journal of Environmental Science and Technology estimated the climate impact of replacing fossil fuel-powered processes with green hydrogen under different hydrogen leakage scenarios in four industries: fertilizers, buses, heavy-duty trucks, and steelmaking.³ The study found that even under the highest emission scenario of 10%, green hydrogen reduced the climate impact of these industries by at least 60% over ten and one hundred years.⁴ However, the study also emphasized the importance of minimizing leakage to maximize the climate benefits of green hydrogen. Under a low leakage scenario of 1%, green hydrogen reduced the climate impact of all four industries by 90% over ten and one hundred years.⁵

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Footnotes

1. Ocko, I. B., & Hamburg, S. P. (2022). Climate consequences of hydrogen emissions. Atmospheric Chemistry and Physics, 22, 9349–9368. https://doi.org/10.5194/acp-22-9349-2022 ↩

2. Ibid. ↩

3. Sun, T., Shrestha, E., Hamburg, S. P., Kupers, R., & Ocko, I. B. (2024). Climate Impacts of Hydrogen and Methane Emissions Can Considerably Reduce the Climate Benefits across Key Hydrogen Use Cases and Time Scales. Environmental Science & Technology, 58(12), 5299-5309. ↩

4. Ibid ↩

5. Ibid. ↩