Hydrogen Isn’t The Answer: 0.7-1.5 Billion Tons CO2e Would Make It A Climate Liability
Hydrogen is often presented as the clean-energy solution capable of decarbonizing the trickiest sectors, including heavy industry, aviation, maritime shipping, and long-haul trucking. Yet, a growing body of evidence makes it clear that a hydrogen economy, at scale, would deliver a major setback to global climate goals rather than helping achieve them. The most recent numbers suggest between 726 million and nearly 1.5 billion tons of CO2-equivalent emissions every year.
I wish I were making this up, but the EU has funded a project called HYDRA that seems like a perhaps less evil counterpart to the Marvel Universe’s world domination plotting evil Hydra organization. This real-world HYDRA, short for Hydrogen Economy Benefits and Risks, is a four-year, €4.48 million effort that aims to map out exactly how hydrogen leaks at every stage of production, transport, storage, and use could add up to a serious climate threat. Just like its comic-book namesake that sprouts many heads, this project has multiple strands: advanced modeling of hydrogen’s impact on atmospheric chemistry and radiative forcing, development of next-generation monitoring tools to sniff out leaks, life-cycle assessments that include water and land use trade-offs, and policy briefs aimed at keeping hydrogen deployment in check.
A peer-reviewed study by the HYDRA project’s partner Politecnico di Torino recently published in the International Journal of Hydrogen Energy provides a detailed analysis of hydrogen leakages across the entire hydrogen supply chain and quantifies their potential climate impacts. The numbers presented are sobering: by 2050, hydrogen leaks could reach a staggering 22 million tons per year in conservative scenarios, and as much as 45.3 million tons annually in more expansive forecasts.
When converted to short-term climate impacts using the more appropriate Global Warming Potential over 20 years (GWP20), this translates to between 726 million and nearly 1.5 billion tons of CO2-equivalent emissions every year. These numbers are far too large to ignore, and substantially erode the supposed climate benefits of a hydrogen-focused strategy.
For better or worse, given the lack of a future of hydrogen as an energy carrier, the journal has an impact factor of 8.1, which is quite high. That’s indicative of the degree of hydrogen hype. Expect the narrow journal’s impact factor to drop precipitously as the hydrogen hype bubble continues to implode. Certainly studies like this one put a million sharp pins in the bubble.
The reason hydrogen leakages are so consequential lies in hydrogen’s indirect greenhouse gas effects. Once released, hydrogen interacts with hydroxyl radicals in the atmosphere, which reduces their availability. Because hydroxyl radicals play a critical role in breaking down methane, their depletion extends methane’s lifetime in the atmosphere. In addition, hydrogen also increases concentrations of tropospheric ozone and contributes water vapor to the stratosphere, both of which have warming effects.
The most recent GWP study estimates hydrogen’s GWP20 at around 33, meaning one ton of leaked hydrogen has the short-term warming effect of 33 tons of CO2. Considering that methane itself has a high GWP20 of around 84, extending its lifetime significantly amplifies the climate risk associated with hydrogen leaks. The GWP20 of hydrogen is down slightly from the 2023 study that found 37, with the new modeling approach that included more atmospheric variables.
According to the Politecnico di Torino study, conducted by Trapani and colleagues, hydrogen leakage rates vary widely across the supply chain. Starting at production, electrolysis, widely touted as the future backbone of green hydrogen, is notably problematic. Electrolysis facilities have leakage rates averaging around 4.0%, though real-world values range broadly from a negligible 0.03% to a troubling 9.2%.
Conventional steam methane reforming (SMR) shows average leakage rates of about 0.75%, while SMR combined with carbon capture and storage is similar at about 0.73%. This finding means electrolysis, usually marketed as the cleanest production route, may actually introduce greater climate risks due to its higher leakage rates.
This is not to make black, gray, or blue hydrogen seem saintly, by the way. Between upstream methane leakages, methane slippage during reformation, and CO2 creation during reformation, black and gray hydrogen have massive greenhouse gas problems. Blue hydrogen typically only sees the capture of 80% to 90% of CO2 emissions when everything is working well and being monitored, something conspicuously absent in most carbon capture efforts. And then there’s the rest of the value chain.
Leakages during hydrogen handling and storage also merit serious concern, especially in processes involving liquid hydrogen. Hydrogen liquefaction is a particularly troublesome step, averaging leakage rates of around 4.4%, with extremes up to 10%. By contrast, compressed hydrogen storage systems exhibit lower worst case leakage rates, typically below 6.5%, depending on pressure and storage duration. Even so, these leakages are far from negligible, given the scale of hydrogen storage anticipated in large-scale supply chains.
Transportation of hydrogen, often overlooked as a significant leakage point, emerges as another area of concern. Transmission pipelines, the proposed backbone for transporting hydrogen at scale, experience average leakage rates of around 1.09%, although these can vary significantly, occasionally approaching 5%. Distribution pipelines show similar characteristics, averaging about 0.83%. Transport by truck raises even more red flags, especially when using liquid hydrogen, where leakages average around 5.3% but can surge as high as 13.2%. Compressed hydrogen transported by tube trailers performs slightly better but still suffers leakage averaging around 1.04%. These logistical challenges substantially complicate efforts to manage hydrogen safely and effectively at the scale required by many global hydrogen scenarios.
At the end-use stage, hydrogen leakages persist. Industrial applications, projected to be the largest users of hydrogen, typically experience leakage rates averaging around 0.36%, with a range of 0.2% to 0.5%. While seemingly small, the sheer volume of hydrogen consumed by industries such as steelmaking and chemicals magnifies the impact.
More troubling are refueling operations, particularly involving liquid hydrogen stations, where average leakage rates rise to 6.3%, reaching as high as 15% during transfers. Fuel cell vehicles, often touted as the future of heavy road transport, add further leakage due to onboard storage and operational losses, with typical leakage rates ranging between 0.56% and 2.64%.
When examining the overall hydrogen supply chain leakage scenarios from the HYDRA study, the picture becomes even clearer. Currently, in 2023, the global hydrogen industry leaks approximately 1.3 million tons annually, representing roughly 1.3% of total hydrogen consumption. By 2030, this leakage rate increases to about 2.2%, representing around 3.2 million tons.
But by 2050, as the proposed hydrogen economy scales dramatically, the numbers become alarmingly high. Under the International Energy Agency’s 2050 scenario, annual hydrogen leakage could rise to about 22 million tons, roughly 5.5% of total hydrogen handled. The Hydrogen Council’s 2050 projections are even worse, estimating leakages at 45.3 million tons per year, or 6.9%. Even the relatively conservative International Renewable Energy Agency (IRENA) scenario forecasts leakage of 24.4 million tons per year, roughly 4.7% of total hydrogen handled.
I’m only somewhat unsurprised by these results. The early papers on various assessments I documented almost a year ago made it clear that hydrogen leaks about 1% or more on every touch point of value chains, for 5% to 10% leakage overall in my assessment at the time. My surprise is that it’s clearly worse than that, with transportation value chains especially being hard to bring down to 10%, and more likely in the 15% to 20% range.
Converting these 2050 leakage scenarios to short-term climate impact using GWP20 reveals just how severe these impacts could be. Under the IEA’s scenario, 22 million tons of leaked hydrogen equates to approximately 726 million tons of CO2-equivalent emissions per year. The IRENA scenario, with 24.4 million tons leaked, yields around 805 million tons of CO2-equivalent annually. The Hydrogen Council’s scenario is most troubling, with leakage of 45.3 million tons translating into nearly 1.5 billion tons of CO2-equivalent emissions every single year. These numbers are large enough to represent significant fractions of current global CO2 emissions, roughly around 38 billion tons per year, severely undermining the climate rationale behind expansive hydrogen use.
Given the magnitude of these leakages, the clear lesson is that hydrogen should be avoided wherever possible as an energy carrier. Instead, hydrogen should be produced only where it is absolutely required, used immediately at the point of production, and handled through the shortest possible value chain. This is exactly what happens today, and it must be exactly what happens in the future.
Current hydrogen sensing technologies struggle to reliably detect concentrations below 30 parts per million, far less sensitive than necessary to detect climate-relevant leaks. Rather than relying on investments such as the recent $20 million allocated by the U.S. Department of Energy to incrementally improve detection capabilities to parts-per-billion levels, the smarter strategy is simply to minimize hydrogen’s role in energy systems. Regulatory frameworks should reinforce this approach by limiting hydrogen applications strictly to essential uses, mandating short and simple supply chains, and ensuring immediate local consumption.
The evidence provided by the HYDRA study should prompt policymakers and industry leaders to reassess the role of hydrogen in energy transitions critically. Green hydrogen, despite its necessary role to displace black and gray hydrogen in industrial processes where there is no alternative, such as ammonia for fertilizers and mining explosives, is not the universal climate solution often claimed.
The road to sustainable energy solutions requires a clear-eyed evaluation of risks and honest communication about their implications. Given the leakage scenarios projected, policy makers considering hydrogen have yet another reason, beyond the sheer cost multipliers it brings to energy and steel making, to stop pursuing it and direct their attention to direct electrification and biological processes.
Sign up for CleanTechnica's Weekly Substack for Zach and Scott's in-depth analyses and high level summaries, sign up for our daily newsletter, and follow us on Google News!
Whether you have solar power or not, please complete our latest solar power survey.
Have a tip for CleanTechnica? Want to advertise? Want to suggest a guest for our CleanTech Talk podcast? Contact us here.
Sign up for our daily newsletter for 15 new cleantech stories a day. Or sign up for our weekly one on top stories of the week if daily is too frequent.
CleanTechnica uses affiliate links. See our policy here.
CleanTechnica's Comment Policy
