Some in the global fight against climate change have argued that the switch to hydrogen powering every fuel cell will become a cornerstone in the battle. Unlike fossil fuels, there is no greenhouse gas (GHG) emissions at use, assuming that hydrogen is burned. But new research indicates that we need to take seriously the climate consequences of hydrogen leaks, particularly as world governments and industries roll out their hydrogen ambitions.
Scientists at MIT take a deeper look at the chemical findings from the leaked hydrogen and the effect it has on the atmosphere in a recent study. In contrast to earlier models that promised to exacerbate climate change through hydrogen, the MIT team’s findings point to a more nuanced reality. The researchers used a comprehensive 66 reaction model to find that though hydrogen damages the atmosphere, it earmarks it likely not as badly as had been expected. Although these results underscore the need for leak prevention in hydrogen infrastructure, non of the currently employed technologies represents a reduction in the passivated volume leak rate below the anticipated defaults in the production and distribution process.
The Role of Atmospheric Chemistry
To allow for leak free storage, hydrogen is stored under high pressure and when leaked and stored in the atmosphere it will react with the hydroxyl radical (OH), which is the ‘detergent of the atmosphere’. OH is critically important as the agent that breaks down methane, the most potent GHG. Because hydrogen reduces availability of OH, methane remains longer in the atmosphere, and even indirectly helps warm. But the 2022 study that first found evidence of this depletion relied upon a simplified four reaction model. But the MIT study’s 66 reaction model considers feedback loops that help offset some of these effects.
“Our model reveals that as hydrogen decreases OH levels and methane accumulates, the resulting methane can actually produce more OH through secondary reactions,”
explains Candice Chen, a Ph.D. candidate and lead researcher. This feedback mechanism reduces the estimated climate impact of hydrogen leaks by about 85% compared to the earlier model.
Comparing Hydrogen and Methane
The study also helps illuminate how large hydrogen’s climate effects are compared with methane, the chief ingredient of natural gas. The MIT team’s analysis found that the impact of both gases, leaked, are risks but that that of hydrogen is about one third that of methane on a per mass basis. This distinction is critically important when policymakers examine hydrogen as a substitute for natural gas in a range of applications.
“Switching to hydrogen can eliminate combustion emissions and potentially reduce climate impacts if leak rates are kept extremely low,”
notes Chen. However, the researchers caution that hydrogen’s GHG effects are “non-negligible,” emphasizing the need for robust leak prevention measures.
Implications for Infrastructure
The outcomes have implications for the design of a hydrogen infrastructure. To make hydrogen a low carbon fuel, minimising leaks is going to be a key part. This study suggests that meticulous monitoring and maintenance protocols must be established to minimise leakage from hydrogen pipelines, storage facilities, fueling stations.
Additionally, the researchers argue for transparent and flexible modelling approaches to better inform policy and infrastructure decisions.
“Simpler models can lead to overestimations or underestimations of climate impacts,”
Chen warns. The 66-reaction model provides a balanced approach, capturing critical feedback mechanisms without requiring the computational intensity of more complex models.
When the world moves quickly towards clean energy, hydrogen will be critical. But this is a reminder that no solution is without challenge. While not as harmful as methane leaks, hydrogen leaks, if not managed carefully, can cause problems for reaching climate goals. The prevention of leaks must be prioritised by policymakers and industry leaders and advanced atmospheric models must be integrated into decision making processes.
The realisation of hydrogen’s potential depends on its responsible use in the larger context of decarbonisation. MIT Team’s research shows that understanding the intricate details of atmospheric chemistry is critical to realise hydrogen’s potential as a bedrock of a sustainable energy future.
