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Why co-electrolysis could transform the fortunes of SAF | Spectra by MHI SAF and other biofuels have been hampered by cost and economic uncertainty. Co-electrolysis technology could accelerate production and take-up.

"Germany converted a natural gas power station to run on hydrogen — using the same turbines, the same pipes, and the same workers.

Uniper's Scholven power station in Gelsenkirchen, North Rhine-Westphalia — a gas-fired peaker plant providing flexibility to the German grid — successfully completed a hydrogen co-firing demonstration programme in 2024, operating its Siemens Energy gas turbines on a blend of 30% hydrogen and 70% natural gas. The turbines required no replacement — they were modified through adjustments to the fuel injection system, combustor geometry, and turbine blade cooling systems, all performed by the existing maintenance team using manufacturer-supplied upgrade kits.

The modification cost approximately EUR 8 million for a 600-megawatt gas turbine unit — approximately 1.3% of the cost of replacing the turbine entirely. Siemens Energy has certified the upgraded turbines for operation at up to 50% hydrogen blend without further modification, and has a development programme targeting 100% hydrogen combustion in existing Siemens H-class turbines by 2030.

The strategic implication is significant. Germany has approximately 30 gigawatts of installed gas-fired generation capacity — a fleet that is considered essential for balancing the grid during periods of low wind and solar output. If this fleet can be progressively converted to hydrogen operation as green hydrogen supply increases, Germany avoids building replacement infrastructure while decarbonising the flexible generation capacity it needs most.

The pipes are the same. The turbines are the same. The workers are the same. Only the molecule changed.

Source: Uniper SE & Siemens Energy AG, Germany, 2024