A large-scale power engine has successfully supplied electricity to Spain’s national grid using 100% pure hydrogen fuel. The trial, conducted by technology group Wärtsilä in the northern town of Bermeo, is the first time an engine of this scale has operated entirely on pure hydrogen under real-world grid conditions.

“This is the world’s first demonstration of a large-scale hydrogen engine running on 100% pure hydrogen,” said the company in a press release.

The operation utilized the Wärtsilä 31H2 model, which currently stands as the largest pure hydrogen engine in existence. While previous power plant designs relied on engines that mixed hydrogen with standard natural gas, this test confirms that grid-connected generators can function without any fossil fuel inputs.

Grid-scale technical validation

“The Wärtsilä 31H2 engine, part of the Wärtsilä 31 platform, one of the world’s most efficient multi-fuel 4-stroke engines, shows that hydrogen can move beyond theory into real-world energy infrastructure,” added the company.

According to the company, Spain was selected for the project because the country has established a high percentage of renewable energy sources and is actively trying to decrease its dependence on unpredictable global fuel markets.

This development addresses a major structural problem facing modern electrical grids. International projections indicate that global solar and wind installations will expand by approximately 4,600 gigawatts by 2030.

Because wind and solar electricity production fluctuates based on weather conditions and the time of day, grid operators require highly flexible backup power systems that can start quickly during periods of low generation or high consumer demand.

Addressing renewable intermittency

“Green hydrogen produces no carbon emissions, enabling clean power generation while supporting the decarbonisation of renewable-heavy grids,” highlighted the press release. When wind or solar farms produce more electricity than consumers need, that excess power can run electrolyzers to split water into oxygen and hydrogen gas.

This hydrogen is stored and subsequently burned in engines like the 31H2 to generate emissions-free electricity when weather-dependent sources are offline, ensuring a continuous power supply.

Beyond traditional grid stabilization, the engine platform is engineered to supply electricity to remote regions that lack connection to main power lines. The manufacturer also expects the technology to support industries that require constant, high-volume electricity.

This includes industrial manufacturing operations and artificial intelligence data centers, which face pressure to reduce their carbon footprints while maintaining uninterrupted operational uptime.

Frameworks for future expansion

Following the verification of the engine’s mechanical performance, company officials stated that widespread adoption now depends on external economic factors rather than engineering capabilities.

“Our Wärtsilä 31H2 hydrogen engine is operating on 100% hydrogen and supplying power to Spain’s national grid, demonstrating that large-scale hydrogen engines can provide the flexible, dispatchable sustainable power needed to support future renewable energy systems,” remarked Rasmus Teir, Director of Technology Strategy & Decarbonisation at Wärtsilä.

He concluded that commercial expansion will require governments to establish clear regulatory frameworks, secure investment pathways, and build the physical pipelines and storage facilities necessary to transport sustainable fuels to power generation sites.

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