World’s largest high-temperature electrolyser comes online

The world’s largest multi-megawatt high-temperature electrolyser (HTE) has started up at Neste’s renewable products refinery in Rotterdam. The MultiPLHY pilot project is a collaboration between Neste, supplier Sunfire, trade association CEA and utility Engie, designed to demonstrate that green hydrogen – produced using zero-carbon electricity from renewables – can integrate into existing refining processes to cut fossil fuel reliance and reduce greenhouse gas emissions.

The 2.6 MW solid oxide electrolysis cell (SOEC) system, supplied by German manufacturer Sunfire, operates at temperatures of 850°C to produce more than 60 kg/h of green hydrogen. (Solid oxide technology runs at nearly 10 times the temperature of PEM electrolysers.) By harnessing waste heat, the HTE consumes significantly less electricity than conventional hydrogen production methods, offering a pathway to more efficient and affordable decarbonisation, reports Neste.  

‘This project has given Neste valuable insights into integrating industrial-scale renewable [green] hydrogen production into our refinery,’ says Jukka Kanerva, Senior Vice President for Renewable Refining at Neste. ‘We remain committed to exploring different pathways to replace fossil-based [grey] hydrogen in our refining processes to reduce greenhouse gas emissions.’ Together, the partners aim to validate the electrolyser’s performance and demonstrate the scalability of SOEC technology in industrial conditions, paving the way for wider commercial deployment of HTE in the refining sector.

‘Thanks to their unrivalled efficiency, our high-temperature SOEC electrolysers will be the preferred solution in many applications where waste heat is available,’ comments Nils Aldag, CEO of Sunfire.  

Pierre Olivier, Head of Hydrogen Lab at ENGIE, emphasises the wider potential: ‘High-temperature electrolysis has the potential to make renewable hydrogen more affordable while increasing the energy efficiency of various industrial processes globally.’

For the Clean Hydrogen Partnership, which helped fund the initiative, the project marks a significant step forward. ‘This installation is the largest of its kind in an industrial environment and represents a milestone for both the technology and the clean hydrogen sector,’ says Mirela Atanasiu, Head of Unit Operations and Communication.

First electrolyser delivered to Europe’s flagship PEM hydrogen project

Meanwhile, Plug Power has delivered its first 10 MW GenEco electrolyser array to Galp’s Sines refinery in Portugal, the first component in what will become Europe’s largest proton exchange membrane (PEM) electrolyser installation.  

The array is the first of 10 identical units that will collectively provide 100 MW of capacity by early 2026. Once fully operational, the project will produce up to 1,712 kg/h of green hydrogen, replacing around 20% of the grey hydrogen currently used at the refinery and cutting 110,000 t/y of CO₂ emissions.  

Plug Power CEO Andy Marsh says the delivery marks a turning point for industrial hydrogen: ‘Plug is building the next generation of industrial energy solutions, and our collaboration with Galp shows that large-scale hydrogen is ready today. This system will be a model for what’s possible across Europe’s refining sector and the broader energy industry.’

The project is a central part of Galp’s €650mn investment in green hydrogen and advanced biofuels. Alongside the 100 MW electrolysis unit, the company is also constructing a hydrotreated vegetable oil (HVO) and sustainable aviation fuel (SAF) plant at Sines. The facility is due for completion in 1H2026.

‘Half of all grey hydrogen demand sits today in refineries and chemical plants,’ notes Ronald Doesburg, Executive Vice President for Galp’s industrial business unit. ‘With our first 100 MW, we will have started the decarbonisation of our Sines refinery. It’s a decisive first step for Galp, but also for the industry.’

For Plug Power, the Sines project represents not just its largest deployment in Europe but also a validation of the scalability of PEM technology in heavy industry. The company believes its modular GenEco systems can be replicated across refineries and chemical sites globally, accelerating the shift from fossil to renewable hydrogen.

Plans unveiled for major electrolysis plant in Austria

Elsewhere in Europe, OMV has unveiled plans for one of the Continent’s largest green hydrogen facilities. The proposed 140 MW electrolysis plant (of undisclosed technology) is to be built in Bruck an der Leitha, Austria, and is scheduled for completion in late 2027.

The facility will produce up to 2,626 kg/h of green hydrogen, primarily for use at OMV’s Schwechat refinery near Vienna. By replacing grey hydrogen, the project is expected to reduce up to 150,000 t/y of CO₂ emissions, equivalent to roughly 10% of the refinery’s direct production-related emissions, reports OMV.

If project funding is approved and the project goes ahead, the Bruck an der Leitha plant would rank among Europe’s top five largest electrolysers and become the biggest in Austria and south-eastern Europe. It builds on OMV’s existing 10 MW pilot PEM electrolyser already operating in the country.