Hydrogen for Cogeneration in Flexible operation

Project Information

HyCoFlex

Grant agreement ID: 101138002

DOI

10.3030/101138002

EC signature date 25 January 2024

Start date 1 February 2024

End date 30 April 2027

Funded under

• Climate, Energy and Mobility

Total cost

€ 7 073 275,00

EU contribution

€ 4 442 550,75

Coordinated by

SIEMENS ENERGY GLOBAL GMBH & CO. KG
Germany

Periodic Reporting for period 1 - HyCoFlex (Hydrogen for Cogeneration in Flexible operation)

Reporting period: 2024-02-01 to 2025-09-30

Summary of the context and overall objectives of the project

The HyCoFlex project develops a retrofittable solution package enabling existing cogeneration plants to operate on up to 100 % hydrogen; therefore operating with zero CO2 emissions . It aims to demonstrate a decarbonised, highly flexible combined heat and power (CHP) plant using an upgraded Siemens Energy SGT-400 gas turbine at an industrial site in Saillat-sur-Vienne, France.
Building on the HYFLEXPOWER project, HyCoFlex advances a fully integrated “power-to-hydrogen-to-power” concept. The project combines advanced Dry Low Emission combustion technology, upgraded hydrogen infrastructure and dynamic digital modelling, simulation and optimisation tools to prove the technical, environmental and economic feasibility of hydrogen-based cogeneration plants. HyCoFlex will demonstrate operational flexibilityof power generation with low NOx emissions and cost-efficient hydrogen generation, supporting Europe’s industrial decarbonisation and energy transition goals.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the first reporting period, the consortium completed comprehensive safety studies confirming robust risk management for 100 % H2 operation and obtained the necessary authorisations from French authorities. Modification and maintenance works on the mixing station and plant infrastructure were finalised, ensuring readiness for the 2025 demonstration campaign.
A performance gap analysis based on the HYFLEXPOWER test resultsin 2023 identified improved flashback resistance at constant NOx as a primary design target , along with improved mixing station flow control. High-pressure tests at the Siemens Energy combustion test facility Clean Energy Center (CEC) validated upgraded combustor hardware, confirming substantial progress toward emission and stability goals.
The upgraded mixing-station control was tuned for stable operation under dynamic hydrogen/natural-gas blends. Tests successfully demonstrated ramp-rate capability above 10% power/min and tolerance to ±30 % vol hydrogen fluctuations . The flashback-detection system was verified, preventing hardware damage.
Dynamic simulation and optimisation models were developed to link hydrogen demand in the cogeneration unit with real-time electricity prices, enabling the determination of optimal electrolyser dispatch strategies and capacity sizing, with resulting Levelized Cost of Hydrogen (LCOH) around 5 €/kg. Optimal electrolyser sizing is highly sensitive to the maximum allowable hydrogen blending ratio of the cogeneration plant. An electrolyser dimensioned for 100% H2 blending is not economically or operationally optimal when the system operates under 50% H2 blends.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

HyCoFlex advances the state of the art in hydrogen-fuelled cogeneration by delivering a fully integrated, validated and safe plant concept that goes well beyond prior single-cycle demonstrations. Once completed, the project will have introduced several technological and methodological innovations:
• Advanced hydrogen combustion system: development of a Dry Low Emission combustor capable of stable operation across the full range of NG/H2 blends with 0–100 % H2 while keeping NOₓ below 25 ppmv @ 15 % O2;
• Flexible cogeneration plant operation: proven capability for rapid load changes (> ±10 % load/min) and resilience to ± 30 % H2 fluctuations, ensuring grid-supporting flexibility and reliability;
• Integrated control and safety framework: extension of hydrogen safety concepts from the gas-turbine package to the entire cogeneration system, including the Heat Recovery Steam Generator (HRSG) and auxiliary systems;
• Digital twin and dynamic optimisation tools: coupling of process models with economic optimisation to define cost-optimal dispatch strategies and assess scalability to larger industrial sites;
• Additive-manufactured burner components: validation of 3D-printed hardware for hydrogen operation, reducing lead time and cost while enabling performance.
These achievements position HyCoFlex to reach TRL 7 through the upcoming engine demonstrations, enabling future replication and commercial deployment in industrial and utility-scale cogeneration applications. The outcomes will provide critical input for future hydrogen combustion standards and certification frameworks in Europe.

HyCoFlex demo site at Saillat-sur-Vienne, France