Wärtsilä has begun validation of a 100 per cent hydrogen engine to power Spain's national grid in Bermeo, marking the world's first large-scale demonstration of an engine running entirely on hydrogen. The trial is framed as a milestone for proving that large engine technology can run on fully sustainable fuels and as support for flexible low-carbon power systems in markets pursuing green hydrogen. The Wärtsilä 31H2 engine, part of the Wärtsilä 31 platform, is described as the world's largest pure hydrogen engine and its performance is under verification in Bermeo. The test builds on an earlier hydrogen-ready large-scale engine power plant and is presented as a pathway towards fully renewable power systems that can deliver dispatchable capacity when required. For India the milestone is relevant as the country targets 500 gigawatt (GW) of non-fossil electricity capacity by 2030 and advances the National Green Hydrogen Mission to scale production, utilisation and export of green hydrogen. As renewable penetration increases, hydrogen-capable engines can provide flexible, dispatchable power to maintain grid stability and enable greater integration of renewables at scale. The company already reports that its engines can operate on natural gas blended with up to 25 per cent hydrogen by volume, a capability that is appearing in power generation tenders in India. This was shown in 2022 when Wärtsilä and WEC Energy Group ran an unmodified Wärtsilä 50SG engine on a 25 per cent hydrogen blend at the 55 megawatt (MW) A.J. Mihm power plant in Michigan. The 31H2 advances that foundation by indicating how a large-scale power plant could run entirely on hydrogen. The Wärtsilä 31 based power plant concept is intended to support energy intensive industries such as data centres and manufacturing with flexible sustainable generation and off-grid operation. The firm says the Spanish validation will inform its global hydrogen roadmap and help identify opportunities in markets including India where renewable expansion and green hydrogen investment are creating demand for dispatchable low-carbon power.