UK government study estimates global warming potential of hydrogen
29 April 2022
There is an increasing body of evidence that leakage of hydrogen to the atmosphere will have an indirect warming effect on the climate and so should be minimized, according to a recent study by the UK Department for Business, Energy & Industrial Strategy (BEIS). The report, Atmospheric implications of increased hydrogen use, was commissioned by BEIS and conducted by the University of Cambridge and the National Centre for Atmospheric Sciences with the University of Reading [5477].
While hydrogen is not a greenhouse gas itself, it reacts with other species such as methane, ozone, and water vapor in the atmosphere to increase their global warming potential (GWP).
The study estimated the GWP of hydrogen over a 100-year horizon (GWP100) to be 11 ± 5—a value more than 100% larger than previously published calculations. Over a time period of 20 years, the GWP20 value for H2 was found to be 33, with an uncertainty range from 20 to 44.
The GWP100 value of 11 is about double the value of 5.8, often quoted in older literature. The main reason for the discrepancy is that while older studies considered hydrogen-induced changes in methane and ozone in the troposphere, the current analysis also considered previously ignored changes in water vapor and ozone in the stratosphere in the GWP calculations.
Due to its very small molecule and its low density, hydrogen gas has a high propensity to leakage, which could present a problem with the ‘global hydrogen economy’ that is envisioned by climate policies. “Leakage of hydrogen into the atmosphere during production, storage, distribution and use will partially offset some of the benefits of a hydrogen-based economy,” noted the report. “Minimization of leaks needs to be a priority if hydrogen is adopted as a major energy source.”
Source: UK government