Jakarta, INTI - Wärtsilä Energy successfully operated its latest 100% hydrogen engine, supplying electricity to the Spanish national electricity grid in Bermeo, Spain. This success marks the world's first demonstration of a large-scale hydrogen engine operating entirely on pure hydrogen.
This achievement marks a significant step in the development of hydrogen-based power generation technology. The test demonstrates that an engine-based power plant can operate on 100% hydrogen fuel under real-world grid conditions, paving the way for the wider deployment of similar technology in the future.
Wärtsilä stated that this technology is becoming increasingly relevant with the increasing penetration of renewable energy sources such as solar and wind power. Green hydrogen is considered capable of acting as an energy storage medium and a backup power source when renewable energy production declines, thereby helping to maintain the reliability and stability of the electricity system.
The Wärtsilä 31H2 engine used in the test is part of the Wärtsilä 31 platform, one of the most efficient multi-fuel four-stroke engines in the world. This engine is also claimed to be the world's largest pure hydrogen engine, and is currently undergoing performance validation at the Bermeo facility.
Designed to Supply Flexible and High Energy
Wärtsilä's Director of Technology Strategy and Decarbonization, Rasmus Teir, stated that one of the biggest challenges in the energy transition is maintaining a reliable electricity supply when renewable energy production declines or when electricity demand surges.
He added that the success of the Wärtsilä 31H2 engine, operating on 100% hydrogen and supplying electricity to the Spanish national grid, demonstrates that large-scale hydrogen engines can provide flexible, schedulable power and support future renewable energy systems.
In addition to the national electricity system, Wärtsilä 31-based power plants are also designed to support sectors with high energy needs, including artificial intelligence (AI) data centers, manufacturing facilities, industrial parks, and off-grid electricity applications.
Spain was chosen as the test site because it is one of the most aggressive countries in developing renewable energy and reducing dependence on fossil fuels. These conditions make the country an ideal location to test the potential of hydrogen technology to support future energy systems.
In June 2026, Wärtsilä customers from various countries witnessed the engine's operation as part of the commercial validation process for the company's latest hydrogen technology.
Trial in Bali with PLN IP
Wärtsilä's commitment to developing hydrogen technology has also been demonstrated in Indonesia. In November 2025, Wärtsilä, together with PLN Indonesia Power, successfully conducted a hydrogen blending trial on a Wärtsilä 50DF engine at the Pesanggaran Power Plant in Bali.
The test achieved a hydrogen blend of up to 23% at partial load and demonstrated better combustion efficiency and lower carbon dioxide emissions compared to using pure natural gas.
Wärtsilä Energy's Energy Business Director Australasia, Kari Punnonen, said that the successful trials in Bermeo and Bali demonstrated the flexibility of Wärtsilä's engine technology, ready to handle a wide range of low-carbon fuels in the future. Through collaboration with customers and partners in Indonesia, Wärtsilä continues to explore opportunities to utilize this technology to support the national clean energy transition.
Conclusion
Wärtsilä Energy successfully tested the world's first large-scale power plant operating on 100 percent pure hydrogen, supplying electricity to the Spanish national grid in Bermeo. This success demonstrates that hydrogen-based power plants can operate reliably under real-world grid conditions and support the integration of renewable energy sources such as solar and wind. The Wärtsilä 31H2 is designed to meet the energy needs of high-power sectors, including AI data centers, industry, and off-grid environments. In addition to Spain, Wärtsilä has previously tested hydrogen blending at a power plant in Bali with PLN Indonesia Power.
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