Topsoe plant promises 30% efficiency boost for green hydrogen

The catalysis and chemical engineering firm Topsoe has cut the ribbon on a manufacturing plant for solid oxide electrolysis cells (SOECs), an emerging technology for electrolytic hydrogen production. The project is a vote of confidence in the long-term prospects for green hydrogen, despite recent sobering developments in the market.

The 23,000 m³ site in Herning, Denmark, is starting with the capacity to produce 500 MW worth of SOECs per year and has room to scale up to 1.5 GW as demand increases. It cost around $345 million to build and received $103 million in support from the European Union.

Kim Hedegaard, a Topsoe executive, said on a call with reporters that the cells are 20–30% more energy efficient than incumbent green hydrogen equipment, which uses alkaline or proton-exchange membranes to split water into hydrogen and oxygen. “The technology that we have designed and developed operates at around 800 °C,” Hedegaard said, compared with 70–90 °C for the incumbent cells. “That’s the fundamental difference and where you get two-thirds of your efficiency gain.”

That enhanced efficiency saves operational costs, Hedegaard said, but it also means the customer doesn’t have to spend as much on supporting power generation equipment. “Read that in the context of not only 30% less electricity, it’s also 30% less generation of renewable energy,” he said. “So, 30% less solar panels, 30% less infrastructure, 30% less wind turbines.”

Reducing the need for supporting infrastructure will be key to the adoption of SOECs, says Alexander Koukoulas, a cleantech expert at the chemical engineering firm Afry. “We’re excited about the technology, as it would be a game changer for green hydrogen,” he says.

The efficiency gains pencil out from a chemical physics standpoint, according to Quan Zhuang, a research scientist at the Canadian government lab CanmetENERGY Ottawa. But Topsoe and other firms commercializing SOECs still need to prove that the systems can stand up to thousands of hours at high temperatures and pressures. “I think Topsoe may be overstating the status” of the technology, he says.

The first 100 MW of cells to roll off the assembly line are headed to coastal Texas, where Topsoe customer First Ammonia is building a plant slated to make 300 metric tons (t) per day of green ammonia from electrolytic hydrogen generated with renewable electricity. The plant, set to begin construction early next year, will use an ammonia synthesis system also supplied by Topsoe.

The Texas facility will, in some ways, be a scaled-up version of a pilot plant Topsoe turned on in 2024 in western Denmark. It has the capacity to make 3,000 t per year of green ammonia powered by solar and wind.

A few days before the ceremony in Denmark, Topsoe announced a project in Galicia, Spain, where the specialty chemical firm Forestal del Atlántico plans to use 55 MW of Topsoe SOECs, along with Topsoe’s process for producing methanol from hydrogen and carbon dioxide. Forestal expects to make a final decision on that project in the second half of 2026 and begin operations in 2028.

The developments are welcome news for the green hydrogen industry, which has recently faced project cancellations and the loss of federal subsidies in the US. The industrial gas giant Air Products and Chemicals, for example, has backed out of more than $3 billion in green hydrogen investments since this time last year. Yet other players in the space are moving ahead.

Hedegaard said the low-carbon hydrogen market is correcting itself after a period of hype. Industry watchers should expect consolidation of projects and companies, he said, but the fundamental business case remains strong.

Topsoe itself is slowing its timeline on a 1 GW SOEC manufacturing plant planned for Chesterfield, Virginia. The delay is a response both to the loss of federal tax credits and slower projected growth in demand for electrolyzers in the US. “I wouldn’t say that we have canceled it or that we have mothballed it. I think right now we are making sure that it is timed to match the demand in the American market,” Hedegaard said.

In fact, he said, North America is the world’s most mature market for green hydrogen and the electrolyzers needed to make it. Canada’s target to blend 10% renewable methane into its natural gas grid is one driver, and several firms are developing projects that would make green ammonia in the US for export to Europe, which is First Ammonia’s plan.

Africa and the Middle East, with their abundant sunshine, are also looking to capture a share of Europe’s green ammonia market, Hedegaard said. In Europe, the interest is in ammonia as a hydrogen carrier, maritime fuel, and fertilizer. China, meanwhile, sees green hydrogen as a way to fill a gap in the supply of low-carbon products left by retrenchment in the US, he said. And sustainable fuels projects proposed around the world all require ample low-carbon hydrogen.

Afry’s Koukoulas says Topsoe’s investment in Herning puts it in a good position to meet long-term growth in demand for green hydrogen. “As deployment accelerates, the potential for lower-cost hydrogen is set to transform fuels and chemicals, where carbon intensity dictates market access—especially in Europe’s demanding low-carbon landscape,” he says.