Award-winning projects push gas turbines to 100% hydrogen

The award was presented at Clean Hydrogen Partnership’s Hydrogen Research and Innovation Days 2025, an event geared towards mapping the sector’s key priorities for the next decade.

One of those priorities is developing advanced combustor technologies capable of operating with 100% renewable hydrogen in modern gas turbines.

According to Clean Hydrogen Partnership, hydrogen is a highly reactive fuel that burns faster than natural gas, creating challenges for combustion systems. Maintaining flame stability, preventing flashback, and controlling emissions at high pressure are all critical hurdles that FLEX4H2 and HELIOS are working to overcome.

To this end, HELIOS has developed a retrofittable hydrogen gas turbine based on the FlameSheet platform, achieving fully hydrogen-powered operation, and FLEX4H2 has designed a fuel-flexible combustor capable of operating with up to 100% hydrogen blended into natural gas. 

It’s these developments that earned the two projects the title of Best Success Story.

FLEX4H2 is being coordinated by Italian turbine specialist Ansaldo Energia. The FLEX4H2 project builds on Ansaldo Energia’s constant pressure sequential combustion (CPSC) technology, already in use in heavy-duty gas turbines. 

FLEX4H2 has completed the design and testing of a first-generation combustor capable of operating at 100% hydrogen with a stable flame and ultra-low emissions. The design, states Clean Hydrogen Partnership, also enables smooth switching between natural gas and hydrogen, offering the fuel flexibility that operators need.

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According to Ansaldo, this recognition highlights the results achieved by the project, which confirm sequential combustion can handle any blend of natural gas and hydrogen, including pure hydrogen, making it a viable solution for the future energy landscape.

Andrea Ciani, Project Coordinator at Ansaldo Energia, said during the award ceremony: “Hydrogen deployment in gas turbines will be a key enabler for clean electricity production and future grid stability. This achievement reflects the strength of a committed team that brings together scientific, technical, and industrial expertise.”

HELIOS is working to advance Netherlands-headquartered Thomassen Energy’s FlameSheet technology, which features an aerodynamically stabilised flame and ultra-low NOx emissions. 

According to Clean Hydrogen Partnership, the project has already completed high-pressure tests with 100% hydrogen and developed a quartz-glass burner model to visualise flashback events for the first time under these conditions.