The trial took place at the company’s Bermeo facility in northern Spain, where a new Wärtsilä 31H2 engine supplied power to Spain’s national electricity network during validation testing. According to the company, the demonstration marks the first time a large-scale engine running entirely on hydrogen has operated under real grid conditions.

The trial reflects growing interest in technologies that can provide flexible generation alongside increasing volumes of wind and solar power. While renewable generation continues to expand, grid operators still need sources of dispatchable power when renewable output falls or electricity demand increases. Hydrogen is attracting growing interest because it can store surplus renewable electricity and be used later to generate power when needed.

Wärtsilä said the trial was designed to demonstrate that large-scale engine-based power generation can operate entirely using hydrogen rather than conventional fuels.  

Rasmus Teir, Director of Technology Strategy and Decarbonisation at Wärtsilä, said the test addressed one of the key challenges facing electricity systems with growing shares of renewable generation.  

‘As countries rapidly scale wind and solar energy, one of the biggest challenges facing the energy transition is how to maintain reliable electricity supplies sustainably during periods of low renewable generation or spikes in demand,’ he said. ‘Today, our Wärtsilä 31H2 hydrogen engine is operating on 100% hydrogen and supplying power to Spain’s national grid, demonstrating that large-scale low-carbon hydrogen engines can provide the flexible, dispatchable sustainable power needed to support future renewable energy systems.’

The Wärtsilä 31H2 is based on the company’s Wärtsilä 31 engine platform, which is used in both power generation and marine applications and offers a power generation capacity of between 4.6–10.4MW, depending on configuration. The company describes the 31H2 as the world’s largest pure hydrogen engine, with performance testing continuing at the Bermeo site.

The company contends that hydrogen-fuelled engines could eventually support a range of applications including power systems with high levels of renewable generation, industrial facilities and energy-intensive operations requiring flexible low-carbon power.

The trial does not mean hydrogen-based power generation is ready for widespread deployment, as the availability of low-carbon hydrogen, supporting infrastructure and project economics remain significant challenges. However, the demonstration provides evidence that large-scale hydrogen engines could become one option for balancing electricity systems as renewable generation continues to expand, notes Wärtsilä.