Hydrogen is fuelling climate change – should we scrap plans to use it?

SINGAPORE - For years, there has been growing interest in hydrogen, or H2, in Singapore and other nations as a cleaner energy source for power plants, industry and shipping.

It has long been used in oil refining and the production of fertilisers and chemicals. Long eyed as a clean-burning fuel, governments and companies see the gas as a key tool to decarbonise the global economy.

Singapore has approved the

mixing of hydrogen with natural gas in next-generation power plants

and has been exploring the use of

hydrogen-based fuels in the maritime sector

to lower the nation’s carbon footprint.

Globally, there are investment plans to produce green hydrogen via renewable energy, instead of fossil fuels. But there’s a catch: hydrogen production is also fuelling climate change. Just how much has been revealed in a global study published on Dec 18.

So, can hydrogen still be a climate solution or are the risks too great?

How does H2 fuel climate change?

Naturally occurring hydrogen is not a greenhouse gas. But it does influence the chemistry of the atmosphere by prolonging the lifespan of methane, a potent greenhouse gas, and triggers the production of ozone and water vapour, both of which also trap heat.

Methane, the main component of natural gas, is produced by fossil fuel production and extraction, wetlands and livestock – for example, burping cows and sheep. It is responsible for about a third of global warming to date.

Hydrogen levels have been steadily growing in recent decades and this is causing more methane to remain in the atmosphere for longer, further driving global warming. This is because hydrogen is disrupting the natural mechanisms responsible for removing methane from the atmosphere.

In the atmosphere, hydrogen interacts with a “cleaning molecule” – short-lived hydroxyl radicals – that oxidise methane. As hydrogen levels rise, it competes with methane for these cleaning molecules, reducing the rate at which methane can be removed. Moreover, the oxidation of methane results in the production of more hydrogen, perpetuating the cycle.

To make matters worse, methane levels in the atmosphere, mainly through human activity such as leaky oil wells, gas pipelines and rice cultivation, have been steadily rising as well.

What are the study’s key findings?

More than three dozen scientists from nearly 30 scientific institutions globally were involved in the study published in the journal Nature. It was Ied by the Global Carbon Project, an international scientific consortium that measures and analyses greenhouse gases produced by humans and nature.

The researchers looked at the historical growth of hydrogen levels in the air and the sources and sinks (removal) to create a global budget. Key sources are fossil fuel production, industrial hydrogen production from fossil fuels and the oxidation of methane in the atmosphere.

About 70 per cent of all hydrogen emissions are removed from the air by soils, largely through bacteria that consume hydrogen as a source of energy. But each year, more is added than is removed from the atmosphere.

The researchers found that hydrogen levels in the atmosphere increased between 1990 and 2020, contributing 0.02 deg C to the nearly 1.5 deg C rise in average temperatures since the pre-industrial period. While this is a small amount, it is at risk of growing, depending on future hydrogen usage, leakage rates and methane emissions.

And that is where the future methods of production can make a big difference, Dr Pep Canadell, executive director of the Global Carbon Project and a co-author of the study, told The Straits Times.

He explained that transitioning from fossil-fuel-based hydrogen production to using renewable energy offers a dual advantage. This green approach involves using electricity to split water into oxygen and hydrogen.

The first benefit is replacing the carbon dioxide-emitting source of energy for the process, and second is eliminating leaking methane. But efforts should be made to ensure that hydrogen production itself does not contribute to leakage.

How is H2 used?

Global hydrogen demand increased to almost 100 million tonnes in 2024, according to the International Energy Agency. Only about 1 per cent of this amount was green hydrogen, although this is expected to gradually increase by 2030 and accelerate after that as production costs come down.

Singapore’s Energy Market Authority has said that by 2030, there will be at least eight hydrogen-compatible power plants in the Republic.

In addition to use in power generation, hydrogen is a key feedstock to make fuels such as ammonia and methanol that can be used to power ships. Some ships are already using green methanol, and engines have been developed to use ammonia, too.

Ports, including Singapore, have been developing bunkering safety protocols for these fuels. For example, the Maritime and Port Authority of Singapore said in November that it will issue licences to supply methanol as marine fuel in the Port of Singapore from Jan 1, 2026.

There is also promise in using green hydrogen as a key fuel source in steelmaking, too, and in chemical production.

Should we halt H2 usage plans?

No. Green hydrogen, though still costly, does hold the promise of less polluting energy that can be part of a suite of low or zero-carbon solutions to shift the world away from fossil fuels.

But production needs to be as leak-proof as possible. And the production of oil and gas also needs to clamp down on methane leaks as well. Investment plans and policies should focus on accelerating green hydrogen production while working to reduce its costs.

Dr Canadell said that the study is a reminder that all the pollution and gases released into the atmosphere from industrial activities have consequences for the planet.

“In some instances, such as the case of hydrogen, gases interact in the atmosphere in complex ways that we are just beginning to understand, and therefore the need to stop using the atmosphere as our dumping ground.”