Hydrogen leakage can actually worsen climate change

U.S. President Joe Biden has set aside $ 8 billion ($ 11 billion) to build at least four “hydrogen hubs” where the fuel will be produced and used, and states are preparing to compete. U.S. service companies, which now supply natural gas, see it as a lifesaver, announcing more than twenty-two hydrogen pilot projects in the past two years.

“Now is when decisions are made, and money is spent,” Ms. Ocko said. “We can move this issue forward now, so it shouldn’t be a problem.”

She and others sounding the alarm insist there is no reason to give up hydrogen. Rather, the heat-trapping power of hydrogen means that any future system for producing, distributing and using the gas must be built to minimize leaks.

“Keep hydrogen leaking low”

“There is great potential to use hydrogen to save a lot of carbon dioxide emissions, but it’s really important to keep hydrogen emissions low,” said Nicola Warwick, lead author of the UK study and a research scientist at the National Center for Atmospheric Science. at the University of Cambridge.

The hydrogen industry acknowledges the problem, even if companies disagree on the possible scope. Dave Edwards, with industrial gas company Air Liquide, said the effects of hydrogen leaks on the atmosphere should be much less than the traditional fuels they displace. Running cars and trucks on hydrogen fuel cells would have less of an atmospheric effect than running them on gasoline and diesel, even if the system for making and delivering that hydrogen leaks.

“It doesn’t mean it’s not important yet, it doesn’t mean we don’t need to understand more about it, but our first impression is that it’s much, much smaller,” said Mr. Edwards, director of the company and its company. a leading hydrogen activist in the United States. Hydrogen leaks, he said, “are manageable problems to deal with.”

Hydrogen has great benefits as a pure fuel. Burn hydrogen in a turbine, and it will generate power without carbon dioxide. Run it through a fuel cell, and it will produce electricity with water vapor as the only exhaust. Unlike solar and wind energy, it can be stored in large quantities for when it is needed. While the vast majority of the hydrogen produced today is stripped of natural gas, in a process that releases carbon dioxide, it can also be separated from water using renewable power, with no emissions but oxygen.

Hydrogen can slide easily through equipment

But for all its advantages, hydrogen can also slide easily through equipment designed to contain larger molecules such as methane in natural gas.

Once it escapes, much of the liquefied hydrogen will be absorbed by microbes in the soil. Some of what is left in the air will react with a substance that helps remove methane from the atmosphere. This is a problem because methane is itself a powerful greenhouse gas, with more than 80 times the global warming potential of carbon dioxide in 20 years. The reaction between hydrogen and that substance – known as the hydroxyl radical, or OH – leaves less of the OH available to react with methane. So methane entering the atmosphere will stay around longer and do more damage than it would have if the hydrogen were not there.

Liquefied hydrogen also has other heating effects. In the troposphere, the closest atmospheric layer to the ground, it triggers a chain of chemical reactions that produce more ozone, another greenhouse gas, and a key component of fog. Much higher up, in the stratosphere, hydrogen leads to an increase in water vapor, which has the general effect of trapping more thermal energy into the atmosphere.

These reactions take place over a short period of time – a handful of years. Excess carbon dioxide, by contrast, has been building atmospheric heat for centuries. But with temperatures rising rapidly worldwide, scientists say short-term drivers of climate change cannot be ignored.

“These decades are important,” said Steven Hamburg, EDF’s chief scientist. His group has tried to raise the issue of hydrogen’s warming potential with anyone who will listen, informing academics, businesses and the U.S. Department of Energy. His colleague, Ms. Ocko, estimates that they have met with about 200 people so far. For EDF, it is a logical extension of the group’s work trying to direct public attention to short-term climate pollutants such as methane and carbon black, which are often overlooked in the focus on carbon dioxide.

Recipe for leaks

Many utility companies are experimenting with mixing hydrogen in their existing natural gas pipelines, spreading networks that feed everything from power plants to domestic furnaces.

To Mr. Hamburg, this is a recipe for leaks. He also warns that mass production of hydrogen from fossil fuels could even lead to a short-term increase in warming if the systems for making and transporting the hydrogen leak enough hydrogen and methane. There would still be a long-term benefit of cutting carbon dioxide emissions. But over the course of a decade or two, a liquefied hydrogen system based on fossil fuels could cause more warming than trade as usual.

“For several decades, you could have been worse off – it’s very credible,” Hamburg said.

The matter did not prevent gas supplies from investigating hydrogen mixing projects. But it can become one of the things that these projects study. California utility PG&E announced plans last month to test different mixtures of hydrogen and natural gas in a dedicated pipeline system separate from the company’s usual gas transmission network, with the mixtures being burned at a power plant south of Sacramento. PG&E-spokeswoman Melissa Subbotin said the company’s “Hydrogen to Infinity” project would examine the potential for leaks.

“Extensive research needs to be done to understand the feasibility of hydrogen injection within a natural gas pipeline system,” she wrote in an email.

Mr Hamburg said a leaky hydrogen economy would simply undermine its own efficiency, giving less impact on climate change than it could. Clean energy advocates point to methane leaking from natural gas wells and pipelines – a leak that has been much more widespread than previously thought – undermined some of the benefits of moving coal-fired power plants from gas to gas. They don’t want that to happen with hydrogen.

“We risk continuing with the construction of new infrastructure that will essentially repeat all of that past damage,” said Julie McNamara, deputy director of climate and energy at the Union of Concerned Scientists. “We don’t have the time or the luxury to misunderstand it.”

Bloomberg

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