One of the fuels postulated as the main solution for emissions released into the atmosphere by fossil fuels, is hydrogen. A fuel that can be used to store, transport and sell renewable energy. However, like any new technology, its use can have serious consequences for the environment.

Based on a new study published in Nature, researchers at Princeton University found that if enough hydrogen leaks into the atmosphere, it can prolong the presence of another greenhouse gas in the atmosphere, hydrogen. methane. A gas that, according to the United Nations Environment Program (UNEP), is a potent greenhouse gas responsible for at least a quarter of current climate warming. It’s also about 25 times more potent than carbon dioxide, but it doesn’t stay in the atmosphere as long.

“Hydrogen is theoretically the fuel of the future,” explains the study’s lead author, Dr. Matteo Bertagni, researcher at the High Meadows Environmental Institute at Princeton University, in the United States. “In practice, though, it raises many environmental and technological concerns that still need to be addressed,” he added.

The problem boils down to a molecule known as hydroxyl radical (OH). Often referred to as ‘the detergent of the atmosphere’, OH plays a key role in eliminating greenhouse gases such as methane and ozone. However, this radical also reacts with hydrogen gas, and since a limited amount of OH is generated each day, any increase in hydrogen emissions results in more OH being consumed to split hydrogen, leaving less OH available to split methane. . As a result, methane would remain in the atmosphere for longer, increasing its impact on the environment.

“It is imperative that we are proactive in setting boundaries”

Furthermore, according to Bertagni, the effects of a hydrogen spike, which could occur as government incentives for hydrogen production expand, could have climate consequences for the planet for decades. “If any hydrogen is emitted into the atmosphere now, it will lead to a progressive accumulation of methane over the next few years,” Bertagni revealed, adding: “Although hydrogen only has a lifetime of about two years in the atmosphere, you still have the methane feedback from this hydrogen 30 years from now.”

The researchers found that if the world switched to a hydrogen-based green economy, but more than 9% of that hydrogen leaked into the atmosphere, the amount of atmospheric methane would increase. Therefore, according to the study, if we transition to a hydrogen-based economy (where hydrogen is produced from methane and emissions are captured and stored), methane emissions must remain below 1% to avoid a negative effect.

Even if methane leaks stayed below 0.5%, hydrogen leaks would have to stay below 4.5% to prevent atmospheric methane from rising. “It is imperative that we are proactive in setting limits for hydrogen emissions so that they can be used to inform the design and implementation of future hydrogen infrastructure,” explains Professor Amilcare Porporato, co-author of the Princeton study.

However, the researchers point out that hydrogen is very small and difficult to capture, which makes it difficult to estimate how much hydrogen will actually leak as more is produced. “Managing hydrogen and methane leak rates will be critical,” confessed Bertagni, adding: “If you only have a small methane and hydrogen leak, the blue hydrogen that is actually produced may not be much better. at least for the next 20 to 30 years.”

Furthermore, the researchers found that, in the worst case scenario, 65% of the benefits of an economy based on hydrogen fuels could be offset by leaks over the next 20 years.

Eventually, however, in the long run, the benefits of hydrogen begin to outweigh the problems of leakage into the atmosphere. In an assumed scenario 100 years from now, the researchers even found that gas leaks could offset 22% of the benefits of hydrogen. “If companies and governments are serious about investing the money to develop hydrogen as a resource, they need to ensure that they do it correctly and efficiently,” says Bertagni, concluding: “Ultimately, the hydrogen economy must be built in a way that does not neutralize the efforts of other sectors to mitigate carbon emissions.”