WORDS BY CHRIS BARANIUK
Illustration by Merijn Hos
In a lab in Ohio, a metal cabinet full of electronics, thin metal piping, and other gizmos is cycling on and off, sputtering out hydrogen gas at irregular intervals.
It’s a prototype electrolyzer—a device that splits water molecules into hydrogen and oxygen using electricity. It does so carefully, without allowing the hydrogen and oxygen to mix. Which would be bad. “That can lead basically to an explosion,” said Paul Matter of Power to Hydrogen (P2H2), the firm that invented the device.
The hydrogen can be burned, stored, and transformed without releasing any carbon dioxide. It could be a clean fuel of the future, its backers say—that is, if the electricity used to produce it is clean, too.
You have to tread carefully, though.
Traditionally, electrolyzers require a slow ramp-up to start, or they run the risk of the hydrogen and oxygen blending together. P2H2’s design, in contrast, has a specialized “hybrid membrane” that prevents mixing, Matter said. It can switch on and off at a moment’s notice and go from zero to full capacity in as little as five seconds. “That’s very important if you want to make hydrogen connected to renewable energy,” Matter added. Hydrogen production can be tied to the vagaries of the sun or wind, for example, but that means the power source is intermittent and unpredictable.
Matter said that in lab tests, P2H2’s device works as intended when hooked up to an electricity supply that mimics the fickle flow of energy you’d typically get from a solar farm. Now, researchers at American Electric Power’s Dolan Technology Center in Columbus, Ohio, are altering the power source to simulate a wind farm’s output instead. Matter said P2H2 hopes to announce commercial pilots of a scaled-up electrolyzer as early as next year.
The venture is one of many that might succeed should the U.S. government’s giant bet on hydrogen payoff. President Biden’s Inflation Reduction Act (IRA) contains an immense $100 billion worth of tax credits for businesses engaged in hydrogen production. Separately, the Bipartisan Infrastructure Law includes $8 billion towards regional “clean hydrogen hubs” intended to supercharge industrial investment in hydrogen technologies.
On its face, it sounds like good news, but not everybody is happy. Hydrogen is increasingly controversial. Not all methods of producing it are environmentally friendly. Some techniques, currently the most common ones, even rely on the extraction of fossil fuels. And there is a heated debate over where hydrogen would be the most appropriate fuel. In some cases, such as personal vehicles, electrification is cheaper and ready to deploy at scale. But in others, like steelmaking, electricity won’t do the job that green hydrogen can. If we don’t get these things right, some say, and put in place guardrails to prioritize truly green hydrogen for things that actually require it, there’s a risk that we rush ahead and mix good intentions with bad technologies. The result could be disastrous.
“We are absolutely opposed to any hydrogen hub in the Delaware River Watershed,” said Tracy Carluccio, Deputy Director of the Delaware Riverkeeper Network, an environmental nonprofit. The Mid-Atlantic Clean Hydrogen Hub group (MACH2), which includes the states of Delaware, New Jersey, and Pennsylvania, will receive up to $750 million from the clean hydrogen hubs funding package.
Hydrogen is, Carluccio asserts, “extremely inefficient.” Hydrogen is an energy carrier. It is, in essence, a fuel that you can make when you have, for example, a surplus of green energy. You can then burn your hydrogen at a later date when you need that energy—perhaps to power a vehicle that would struggle on batteries—a giant cargo ship, for instance.
Hydrogen is increasingly controversial. Not all methods of producing it are environmentally friendly.
But that flexibility comes with a big trade-off. Inevitably, you lose energy turning electricity into hydrogen. P2H2’s electrolyzer loses 20%, for instance. If hydrogen is turned back into electricity again, rather than used for heat or chemical reactions, it’s almost certain that you’ll lose more than half of the energy you started with.
On top of efficiency problems, Carluccio fears that MACH2 will be used to extend the life of fossil fuel-based industries in the region, although the coalition running the project has previously claimed it will not extract fossil fuels. She also argues that hydrogen is unsafe because it can cause explosions when not handled correctly and that, when burned to generate energy, it releases the pollutant nitrogen oxide. The exact extent of pollution remains contentious.
“MACH2 was ranked the greenest hub in the nation. Our goal from the beginning has been to make sure we do hydrogen right. There will be no fossil fuel-based hydrogen in the hub,” a MACH2 spokesperson told Atmos in an email. “A green hydrogen hub in our region means cleaner air, healthier neighborhoods… and creates new good-paying union jobs in the clean energy economy.”
Carluccio complains that there is a lack of detail at present about the specific projects that will comprise MACH2 or any other of the seven hydrogen hubs poised to spring up around the U.S. in the coming decades. The MACH2 spokesperson told Atmos that 97% of hydrogen from the hub would come from electrolysis powered by either renewable or nuclear energy.
Still, Bridget van Dorsten, senior research analyst at research and consultancy group Wood Mackenzie said that we will have to wait to see how everything shakes out: “It won’t really be until late 2020s or late 2030s that these hydrogen hubs are really going to come online.”
There are certainly significant incentives to use carbon-free, renewably generated hydrogen. For example, the IRA tax credit of up to $3 per kilogram of zero-carbon hydrogen is the most generous hydrogen subsidy in the world right now. But even so, the economics of blue hydrogen are hard to beat, says van Dorsten. Blue hydrogen is produced by splitting fossil gas into hydrogen and carbon dioxide, some of which is then captured and stored. It’s roughly half the cost of green hydrogen to produce. However, it has a larger carbon footprint—potentially larger than just burning fossil gas directly—and in general, relies on existing fossil fuel industry infrastructure.
Van Dorsten and her colleagues predict that green hydrogen will dwarf fossil hydrogen by 2050, but it’s very far from doing so currently. In addition to blue and green hydrogen, there is also gray hydrogen, which also uses fossil gas but doesn’t capture carbon dioxide after the fact, pink hydrogen, which uses electricity from nuclear power stations, and gold hydrogen, which generates fuel from residual hydrocarbons in depleted oil wells. The carbon emissions associated with these approaches, along with their ties to the fossil fuel industry, vary greatly.
“I hate the colors,” says Lindsey Motlow, a senior research associate at Darcy Partners, a technology firm that works with the oil and gas industry. “Ultimately, the carbon intensity is what we care about.” She suggests taking a purist’s approach may be risky. By only producing hydrogen using renewable energy and electrolysis, the industry might miss the opportunity to develop other forms of hydrogen production that could be comparatively clean, she said.
Van Dorsten and her colleagues predict that green hydrogen will dwarf fossil hydrogen by 2050.
One project, described as green hydrogen and backed by BP, involves using heat from an industrial plant to lower the amount of electricity required for electrolysis. Other ideas include capturing biogas (methane) and splitting that to get hydrogen. Some academics agree. Hannes van der Watt at the University of North Dakota said he and colleagues are interested in pursuing biogas as a form of green hydrogen. He added that the methane could be sourced from food waste or landfill sites, which would prevent it from entering the atmosphere.
Mark Jacobson at Stanford University, on the other hand, has a simple but strict definition: “Green hydrogen is hydrogen from an electrolyzer where the electricity is from a clean, renewable source.” Anything else is “some other color,” he said.
Environmental groups including the National Resources Defense Council agree with him. They are calling for “guardrails” to ensure that investment in U.S. hydrogen projects does not inadvertently embolden the oil and gas industry or slow down the transition to the cleanest available sources of energy—renewables and electrification.
For example, in their Equity Principles for Hydrogen, the California Environmental Justice Alliance affirmed that green hydrogen only includes that made from electrolysis of water using renewable energy—not from biogas, fossil gas, nuclear plants, or carbon capture and sequestration. Additionally, these renewable energy sources must be new rather than existing, so they facilitate continued rollout and don’t detract from an already insufficient clean energy grid.
They have guardrails for end uses, too: Green hydrogen should be used if and only if direct electrification with renewable energy is not a cheaper, safer, and more efficient alternative. It should not, for example, be used for passenger cars because electric vehicles are already available, or to heat homes because heat pumps and electrification are already feasible low-emissions alternatives. Michael Liebrich’s famous “clean hydrogen ladder” ranks use cases for hydrogen and puts hydrogen fuel cell vehicles and domestic heating near the bottom. Down there with them is using hydrogen to store renewable energy when it’s not needed. Given the energy losses with each transformation between electricity and hydrogen, Carluccio said “it simply makes no sense.”
The fuel, used properly, could help reduce emissions for hard-to-abate sectors rather than slow down the deployment of cheap and ready renewable energy. But as for the Biden administration’s spending spree, without sufficient guardrails to clearly guide how to produce and use it, Jacobson says simply, “Money is being wasted.”
Atmos approached the U.S. Department of Energy on these points. It said the hydrogen hubs were “essential to achieving President Biden’s vision of a strong clean hydrogen economy that creates healthier communities, strengthens energy security, and delivers new economic opportunities across the nation.” Two of the seven chosen hubs will use green hydrogen exclusively, according to the department, and those that produce carbon dioxide must have plans to capture and permanently store it.
The good news is that green hydrogen, if it is truly green, can help reduce emissions. For example, it can reduce emissions in hard-to-decarbonize industries such as ammonia fertilizer production, steelmaking, and oil refining. For one reason or another—because they need high heat, a physical molecule for a chemical reaction, or more power than renewable energy can provide—these industries aren’t easy to electrify. Replacing the millions of tonnes of gray hydrogen they currently use with green alternatives is “low-hanging fruit,” according to van Dorsten. The key factor in getting green hydrogen right is not letting it interfere with other climate solutions that are ready to deploy now and at scale. Beyond obvious applications, it’s probably best to prioritize renewables, electrification, and batteries. “If you want to maximize the impact of green electrons, you use them as green electrons,” she said. “The highest efficiency comes from using electricity as electricity.”
Matter, unsurprisingly, said that out of the various forms of hydrogen now emerging, he thinks green hydrogen—as defined by Jacobson—is what will “win out” in the end. And he hopes his electrolyzer will demonstrate the feasibility of tying hydrogen production directly to renewable energy sites.
It is an exciting prospect, he said, but, like many in his industry, he is aware of rising squabbles over how exactly hydrogen will fit into the energy transition.
“It will be damaging for the hydrogen industry if people become skeptical of it, saying it’s just greenwashing,” he said. “That is a concern.”
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