How much does hydrogen leakage undermine the climate benefit?
Hydrogen is a small molecule that easily leaks into the atmosphere, and it acts as an indirect greenhouse gas. A 2022 study found that if green hydrogen systems have high leakage rates (10%), the climate benefit over the first two decades is only about half that of the fossil fuel technology it replaces — far from the common perception that green hydrogen is climate-neutral [4]. Over a 100-year period, the same high-leakage scenario still reduces climate impact by around 80%, so the problem is most acute in the near term [4].
A separate 2024 analysis confirms this: for green hydrogen, upper-end hydrogen emissions can reduce near-term climate benefits by up to 25% [2]. The same study also warns that if the renewable electricity used to make green hydrogen is not additional to what is already needed to decarbonize the electric grid, the overall warming could be worse than using fossil fuels directly [2]. In other words, green hydrogen only helps the climate if the renewable energy powering it is truly extra, not diverted from other clean uses.
Does green hydrogen work better in some places than others?
Yes, the practical climate impact of green hydrogen depends heavily on geography and climate. A 2026 study comparing South Korea and Saudi Arabia found that Saudi Arabia's consistent solar resource and flat, open land allow for regionally self-sufficient green hydrogen systems with minimal storage and transmission needs [5]. In contrast, South Korea's mountainous terrain and seasonal variability require extensive energy storage and inter-regional transmission, making distributed hydrogen production more cost-effective [5]. This means that green hydrogen's climate benefit is easier to achieve in sun-rich, flat regions with stable renewable output.
Even within a single country, the impact on the power system matters. A 2021 study of Ireland found that introducing electrolysers for green hydrogen production to meet a 70% renewable electricity target actually increased emissions from power generation, because the electrolysers added demand that sometimes had to be met by fossil-fuel plants [6]. This highlights a key catch: green hydrogen is only as clean as the electricity grid it draws from, and in grids that are not yet fully decarbonized, it can paradoxically increase emissions.
About These Sources
This answer is built on 6 peer-reviewed studies — published from 2021 to 2026, 4 from 2024 or later, 3 in Q1 journals, collectively cited 363 times — selected as the most relevant from 9 studies that passed quality screening, drawn from 64 papers retrieved from a database of over 500 million.
Sources used in this answer
Environmental and climate impacts of a large-scale deployment of green hydrogen in Europe
A 2024 life-cycle assessment of large-scale green hydrogen deployment in Europe found that the dedicated renewable infrastructure adds 45% extra climate impact, and while green hydrogen wins on climate, it worsens human toxicity, ecotoxicity, mineral use, land use, and water depletion compared to blue hydrogen.
Climate Impacts of Hydrogen and Methane Emissions Can Considerably Reduce the Climate Benefits across Key Hydrogen Use Cases and Time Scales.
A 2024 reanalysis shows that including upper-end hydrogen emissions can reduce near-term climate benefits of green hydrogen by up to 25%, and if renewable electricity is not additional to grid decarbonization, green hydrogen can cause more warming than fossil fuels.
Cost of Green Hydrogen
A 2024 cost analysis using Monte Carlo simulation found green hydrogen production cost at 5.32 EUR/kg with baseline electricity at 0.053 EUR/kWh, but sensitivity analysis shows electricity price spikes can increase cost by up to 14 EUR/kg.
Climate consequences of hydrogen emissions
A 2022 study shows that green hydrogen with 10% leakage may only cut climate impacts in half over the first two decades, though over 100 years it reduces impacts by about 80%; lower leakage (1%) yields limited climate impact over all timescales.
Evaluation of geographic and climatic impacts on joint planning of green hydrogen and renewable electricity supply chains
A 2026 study comparing South Korea and Saudi Arabia found that Saudi Arabia's consistent solar resource and flat land enable self-sufficient green hydrogen systems with minimal storage, while South Korea's terrain requires extensive storage and transmission.
Green hydrogen for heating and its impact on the power system
A 2021 study of Ireland's power system found that introducing electrolysers for green hydrogen to meet a 70% renewable electricity target increased emissions from power generation and marginally raised electricity prices.