Hydrogen has been billed as the clean energy of the future by governments worldwide, including in the United States, Europe, Australia and Japan.

But a new study published in the journal Applied Energy found making hydrogen from fossil fuels produces “substantial” greenhouse gas emissions that are the driver of global warming, even with carbon capture technology — which captures carbon dioxide before it is released into the atmosphere and pumps it underground.

“Hydrogen made from natural gas leads to more fugitive emissions — methane that is leaked into the environment during the extraction and processing of natural gas — compared to just burning natural gas directly,” said Fiona Beck, from the Australian National University, who co-authored the peer-reviewed paper. “Including [carbon capture and storage] in the process actually increases fugitive emissions further, as more natural gas is needed to fuel the process.”

More than 100 countries, including the United States, signed up to a Global Methane Pledge at a United Nations climate summit in Glasgow, Scotland, this month, vowing to cut methane emissions — a particularly potent greenhouse gas — by 30 percent on 2020 levels by 2030.

Many countries are banking on hydrogen to help lift their ambitious carbon-neutral plans. Some governments have given priority to “green hydrogen,” which uses renewable energy — such as that generated by wind turbines or solar panels — to split water into hydrogen and oxygen.

Others, including the United States, Canada, China, Japan, Korea, Norway and Australia, have made the case for a technology-neutral approach: potentially paving the way for a prominent role for “blue” hydrogen, as it is known, produced from fossil fuels such as natural gas.

In Washington and other world capitals, the natural gas industry has been lobbying for fossil-fuel-based hydrogen to become a reliable, next-generation fuel to be used to power cars, heat homes and burn in power plants. This week’s bipartisan infrastructure package dedicated $8 billion to creating regional hydrogen hubs in the United States.

But scientists have recently started to examine some of the industry claims around hydrogen. A study published by Cornell and Stanford University researchers in August found that the greenhouse gas footprint of blue hydrogen is more than 20 percent greater than burning natural gas or coal for heat.

The ANU researchers compared both the emissions and financial cost of producing hydrogen using fossil fuels or renewable energy. Recent studies have compared these technologies, typically assuming high carbon capture rates, but have not assessed the impact of fugitive emissions and lower capture rates on total emissions and costs, the researchers said.

In many places, there isn’t yet enough renewable energy to produce vast amounts of green hydrogen, and the process remains costly. But that could be about to change, the researchers said, leaving governments that invest heavily in fossil-fuel-based technologies with stranded assets. A recent study suggested that green hydrogen may already be cheaper than blue in Australia, where the country’s abundant sunshine, huge land area and powerful winds have fueled growth in renewables in recent years and lowered costs.

“Our work highlights that large investment in fossil-fuel-based hydrogen with CCS could be risky, locking in a new fossil fuel industry with significant emissions, and one that is likely to be out-competed by renewable technologies in the future,” Beck said.

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