Wärtsilä is testing a hydrogen-powered engine
Wärtsilä Energy has generated electricity for the Spanish national grid using a new engine that runs entirely on hydrogen. The test, conducted in Bermeo, Spain, marks the first time in the world that a large-scale engine has been operated using only hydrogen.
Technology company Wärtsilä has begun testing the world’s first hydrogen-only engine in Bermeo, northern Spain, with the aim of feeding electricity into the national grid.
The test is a significant demonstration that the engine can run on 100% sustainable fuels, such as hydrogen. The test builds on experience gained from Wärtsilä’s previously launched world’s first large-scale 100% hydrogen-ready engine power plant. The test demonstrates that fully renewable energy systems are feasible. Renewable energy production is projected to grow by nearly 4,600 gigawatts by 2030, highlighting the importance of flexible, grid-balancing technologies in situations where wind and solar power generation is insufficient.
Green hydrogen produces no carbon emissions, enabling clean energy production and supporting the goal of carbon-neutral power grids that rely on renewable energy. Excess renewable electricity can be stored in the form of hydrogen, allowing the hydrogen to be used for electricity generation when wind or solar power production is low. This helps stabilize power systems and improve energy security.
The Wärtsilä 31H2 engine, part of the Wärtsilä 31 engine platform—which ranks among the world’s most efficient four-stroke engines—demonstrates that the use of hydrogen can move from theory to practice in energy infrastructure. The Wärtsilä 31H2 engine is the world’s largest engine that runs on hydrogen alone. The engine’s performance is currently being verified in Bermuda.
“This test supports the future of renewable energy production. Wind and solar energy production is growing rapidly around the world, and one of the biggest challenges of the energy transition is ensuring reliable electricity generation in a sustainable manner during periods when renewable energy production is low or consumption spikes occur. Our Wärtsilä 31H2 hydrogen engine is already capable of running on hydrogen alone and generating electricity for the Spanish national grid. “This demonstrates that large-scale hydrogen engines can support future renewable energy systems by providing flexible, sustainable energy exactly when it is needed,” says Rasmus Teir, Head of Technology Strategy and Carbon Neutrality at Wärtsilä.
“We have demonstrated that the technology is ready. The next step is to focus on building an environment that supports its scaling up. This involves, in particular, decisive regulation, a robust investment environment, and the infrastructure needed to accelerate the growth of renewable energy and sustainable fuels, such as hydrogen. The technology is here—now is the time to scale it up.”
The power plant, based on the Wärtsilä 31 engine, is designed to support rapidly growing, energy-intensive sectors—including data centers, manufacturing facilities, and industry—with grid-independent, flexible, and sustainable energy production.
As a pioneer in renewable energy production, Spain is an ideal location to showcase the future potential of hydrogen technologies, as the country seeks to reduce its dependence on fluctuations in the price and availability of fossil fuels.
In June 2026, Wärtsilä’s customers from around the world were able to observe the engine’s test run, marking a significant milestone in its commercial validation.
