Climate Impacts of Hydrogen and Methane Emissions Can Considerably Reduce the Climate Benefits across Key Hydrogen Use Cases and Time Scales

Abstract

Recent investments in "clean" hydrogen as an alternative to fossil fuels are driven by anticipated climate benefits. However, most climate benefit calculations do not adequately account for all climate warming emissions and impacts over time. This study reanalyzes a previously published life cycle assessment as an illustrative example to show how the climate impacts of hydrogen deployment can be far greater than expected when including the warming effects of hydrogen emissions, observed methane emission intensities, and near-term time scales; this reduces the perceived climate benefits upon replacement of fossil fuel technologies. For example, for blue (natural gas with carbon capture) hydrogen pathways, the inclusion of upper-end hydrogen and methane emissions can yield an increase in warming in the near term by up to 50%, whereas lower-end emissions decrease warming impacts by at least 70%. For green (renewable-based electrolysis) hydrogen pathways, upper-end hydrogen emissions can reduce climate benefits in the near term by up to 25%. We also consider renewable electricity availability for green hydrogen and show that if it is not additional to what is needed to decarbonize the electric grid, there may be more warming than that seen with fossil fuel alternatives over all time scales. Assessments of hydrogen's climate impacts should include the aforementioned factors if hydrogen is to be an effective decarbonization tool.

Evaluating the Effect of Hydrogen on the Tensile Properties of Cold-Finished Mild Steel

“…Due to increased interest in lowering carbon emissions by blending natural gas with hydrogen [24,25], there is a renewed interest in HE in low-carbon steel, as such steels are traditionally used to transport natural gas. To achieve such a goal, more studies need to be carried out and more data generated.…”

Evaluating The Effect of Hydrogen on The Tensile Properties of Cold Finished Mild Steel

“…The accumulation of hydrogen at material interfaces can lead to delamination or decohesion, particularly under tensile stress. Due to increased interest in lowering carbon emission by blending natural gas with hydrogen [22,23], there is a renewed interest in hydrogen embrittlement of low carbon steel, as such steels are traditionally used to transport natural gas. To achieve such a goal, more studies need to be carried out and data generated.…”

First detection of industrial hydrogen emissions using high-precision mobile measurements in ambient air

“…Adding up to a global warming potential of 12.8 ± 5.2 over 100 years and a perturbation lifetime of 1.9 ± 0.5 years in the atmosphere, H 2 surpasses carbon dioxide (CO 2 ) in terms of greenhouse gas potency 12,14,25,40,41 . The current estimates of the loss rate potential (including venting, purging and uncontrolled leakage) of anthropogenic H 2 emissions, solely based on models, range from 1-10% of the total production 13,35 . So far, however, these estimates have not been validated at all by actual measurements, due to the lack of appropriate measurement techniques.…”

“…Until now eld campaigns speci cally focused on regional and local anthropogenic H 2 emission sources originating from the hydrogen value chain have been absent. In Sun et al (2024) 35 it is rightly pointed out that: "It is important to note that the rates of hydrogen emissions are currently unknown across the value chain. Empirical measurements are needed to improve our understanding of where emissions are coming from and in what quantities.".…”