In the gas transmission systems, gas turbines in simple and combined cycles, can achieve a significant reduction of atmospheric pollution and greenhouse gases emissions only by transitioning to carbon-free fuels and by increasing the share of RES. However, the volatility in power output introduced by increasingly large shares of RES in the future energy system represents a key challenge. In this context, gas turbines are considered to be the most robust, mature and cost-effective technology, and are bound to reinforce their role as guarantors of grid stability and reliability. To fulfil this role in line with the Paris Agreement’s goals^[1], power generation from gas turbines needs to be decarbonised.

Increase of thermal and mechanical efficiency by adopting cogeneration systems can contribute to reduce the carbon footprint of the industrial sector, even if a substantial decarbonisation can be achieved only by blending increasingly higher fractions of hydrogen into natural gas (the gas turbines conventional fuel). The capability for gas turbines to operate on hydrogen-based fuels is a key future requirement to fulfil the target of CO₂-carbon free power generation. Those play a strategic role in achieving the EU energetic independency from sources external to the community (REPowerEU).

Currently, the maximum volumetric hydrogen fraction, up to which commercially available gas turbines can be operated with, lies between 30% and 50%, depending on the specific gas turbine class and type. Therefore, a significant advancement both in gas turbines combustion systems technology (TRL range up to 6) and in gas turbine product industrialisation (TRL range 6-8) is still necessary.

Project results are expected to contribute to the following outcomes:

• Accelerate the achievement of industrial sector decarbonisation via the retrofitting of existing heat and power generation systems with gas turbines able to burn up to 100% hydrogen, while still guaranteeing low NO_x emissions, high efficiencies and operational flexibility to typical values obtained in natural gas combustion conditions.

Project results are expected to contribute to the following objectives and KPIs of the Clean Hydrogen JU SRIA:

• Demonstrate enhancement of gas turbine flexibility with respect to the state of the art;
• Increase the maximum hydrogen fuel content during the start-up phase;
• Ability to handle increasing hydrogen content fluctuations;
• Increase the minimum ramp rate;
• Increase the level of safety of hydrogen technologies and applications;
• Specifically, the following KPIs are expected to be reached:
  • H₂ content in gas turbine fuel in the range 0 – 100 %vol;
  • NO_x emissions < 25 ppmv @ 15%O₂ (30-100% vol H₂) and < 15 ppmv @ 15%O₂ (0-30% vol H₂);
  • Max H₂ fuel content during start-up up to 100 %vol;
  • Max admitted efficiency reduction in H₂ operation in the range 0.5 – 2 % points;
  • Minimum ramp rate 10 % load / min;
  • Ability to handle H₂ content fluctuations ±30 % vol. / min;
• Maximum admitted power reduction in H₂ operation 0.5 – 2 %points.

Technological development of gas turbines combustion systems is aimed to handle incremental percentage of hydrogen blended in the natural gas as fuel. A further step, in accelerating the energy sector decarbonisation, is to provide gas turbine solutions able to be used with their own flexibility in handling fast load changes over the wider range of natural gas / hydrogen blends up to the full hydrogen composition.

In parallel with the incremental hydrogen availability offer expected for the next years, the required final TRL 7 is pushing gas turbine technology and products development to the commercialisation phase and the fleet replacement and/or enhancement by the end users by new engine solutions able to provide with hydrogen/natural gas blends, similar performances of the current natural gas ones.

Considering the purpose of retrofitting the combustion system in existing gas turbines fleets for the hydrogen combustion, the targeted gas turbine size for cogeneration applications is at least 10 MWe.

A minimum number of 60 (not continuous) fired hours should be achieved, to properly cover the system behaviour characterisation, including typical transient conditions of gas turbine system operations.

A starting TRL 5 is required, which means that the larger part of the technology effort to develop a retrofittable combustion system able to meet the ambitious targets described by the KPI has been already performed at laboratory scale (e.g. for annular combustion system architecture, a full annular rig full pressure and temperature test successfully performed; for can combustion systems, a single can full pressure and temperature test successfully performed).

In order to reach TRL 7 at the end of the project, proposals should therefore include:

• Detailed simulations aimed to define the cogeneration system expected performances and the gas turbine durability (mean time between maintenance in terms of start-stop cycles number and fired hours);
• Development of dedicated safety and plant integration concepts to enable operation of the retrofit GT unit with up to 100% H₂;
• Execution of a field test with a gas turbine equipped with DLE H₂ system:
  • Availability of a gas turbine engine equipped with DLE H₂ system;
  • Availability of required hydrogen amounts to conduit an engine test campaign with respective feed lines, storage system typically required;
  • System behaviour characterisation, including typical transient conditions of the gas turbine system operation (start-up ramp to full load, loads rejections, turndown limits);
  • Transient conditions characterisation, related to fuel composition variation;
  • Real system environment setup of acoustic damping systems;
  • Availability of a demo plant with a cogeneration system and possibility to perform multiple start-stop cycles;
• Evaluation of the legislative barriers, if any, of using co-generation systems including a gas turbine retrofitted with combustion systems able to operate with fuel compositions up to 100% hydrogen.

Applicants should ensure and provide evidence of the availability of hydrogen, as function of the gas turbine size, both in terms of required quantity fulfilment and its storage and feed.

Proposals are expected to collaborate and explore synergies with projects supported under the topic “HORIZON-JTI-CLEANH2-2022-04-04: Dry Low NOx combustion of hydrogen-enriched fuels at high-pressure conditions for gas turbine applications”. In addition, applicants are encouraged to seek synergies with existing projects of the Horizon Europe Process4Planet and Clean Steel partnerships or future topics. In particular with the view of integrating the developed solution(s) into larger scale, real-life applications. Synergies with hydrogen production topics supported by the JU in the current call (such as HORIZON-JTI-CLEANH2-2023-01-07: ‘Hydrogen use by an industrial cluster via a local pipeline network’) maybe considered for the hydrogen supply during demonstrator tests.

Proposals are expected to address sustainability and circularity aspects.

This topic is expected to contribute to EU competitiveness and industrial leadership by supporting a European value chain for hydrogen and fuel cell systems and components.

Proposals should provide a preliminary draft on ‘hydrogen safety planning and management’ at the project level, which will be further updated during project implementation.

Activities are expected to start at TRL 5 and achieve TRL 7 by the end of the project - see General Annex B.

At least one partner in the consortium must be a member of either Hydrogen Europe or Hydrogen Europe Research.

The maximum Clean Hydrogen JU contribution that may be requested is EUR 6.00 million – proposals requesting Clean Hydrogen JU contributions above this amount will not be evaluated.

Purchases of equipment, infrastructure or other assets used for the action must be declared as depreciation costs. However, for the following equipment, infrastructure or other assets purchased for the action (or developed as part of the action tasks): combustion system of the gas turbine and related components needed to retrofit the gas turbine including hydrogen storage and feed, costs may exceptionally be declared as full capitalised costs.

The conditions related to this topic are provided in the chapter 2.2.3.2 of the Clean Hydrogen JU 2023 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2023–2024 which apply mutatis mutandis.

[1] https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement