Naval hybrid propulsion and power systems

TOPIC ID: EDF-2025-LS-RA-SI-ENERENV-NH2PS-STEP

Type of grant: Call for proposals

General information

Programme:

Call: Spin-in EDF research actions implemented via lump sum grants (EDF-2025-LS-RA-SI)

Type of action: EDF-LS EDF Lump Sum Grants

Type of MGA: EDF Lump Sum Grant [EDF-AG-LS]

Status: Forthcoming

Deadline model: single-stage

Planned Opening Date: 18 February 2025

Deadline dates: 16 October 2025 17:00 (Brussels time)

Topic description

The outcome should contribute to:

• Accelerate the adoption of commercial high-tech propulsion and power system components.
• Technology implementation on naval vessels and the accelerated development, prototyping and demonstration of a number of crucial propulsion and power system technology building blocks.
• Accelerate the future research and development programmes of on energy conversion systems.

The EU has set the ambition to be carbon neutral by 2050. This objective also affects military naval vessels. Most efficiently produced carbon-neutral fuels such as hydrogen and ammonia have an energy density, safety and toxicity that does not allow its application on frontline naval vessels, such as frigates and corvettes, as it would affect their ability to operate autonomously, with minimal logistic supply lines and impede the resilience against damage due to the explosivity or toxicity of the fuel. Fluid fuels, such as methanol, could be applicable to certain types of naval vessels with limited autonomy requirements or during peacetime operations, while frontline operations would be best sustained with a zero-emission long-chain synthetically produced fuel, such as sustainable aviation fuel. This drives the need to reduce the impact of sustainable fuels on naval propulsion and electrical power systems. The use of expensive long chain e-fuels and less energy-dense e-fuels, such as methanol, urgently requires an increased energy efficiency of the propulsion and power plant. Moreover, commercially developed technology, such as electrical propulsion systems, novel SiC based power-dense power electronics, DC power systems, fuel cells and energy-dense storage devices (e.g., Li-ion batteries, super-capacitors, flywheels, etc.) with higher capacity provide an opportunity to increase the efficiency, range and life cycle cost of propulsion and power systems, and to improve its military performance criteria, such as noise, infrared and electromagnetic signatures, power density, power system resilience against shock and battle damage. However, to achieve this, these systems need to be developed for military application and integrated in a naval vessel and its propulsion and power system.

This call topic aims to address the design of a prototype, the testbed and general architecture for a future modular and hybrid propulsion systems, hybrid DC power systems and their components for military application, while performing its system integration in a combined digital and physical development environment. These novel propulsion and power systems can achieve reduced Green House Gas (GHG) and hazardous emissions from well-to-wake in peacetime and can power wartime missions effectively with maximum autonomy at sea, survivability and minimal and controllable noise, infrared, electromagnetic and radar-cross-section signatures. To achieve these benefits, mostly civilian developed technology needs to be navalised and effectively integrated in the naval propulsion and power system. These naval propulsion and power systems aim to serve a wide spectrum of naval vessels ranging from small and lightweight high-speed combat vessels, slow speed manhunting vessels and motherships, medium- and high-speed frigates, through to high-speed air-defence destroyers. These vessels have in common that they serve a wide range of propulsion systems, diverse variable speed drives and many DC combat system loads and therefore could all benefit from modular and scalable hybrid propulsion systems and hybrid DC power systems.

Specific objective

In many commercial applications, continually increased power density of electrical motors, generator units and power electronic converters is achieved. Due to the enormous diversity of naval vessels, these novel technologies for propulsion and power generation are only very slowly implemented on naval vessels, while its urgent need increases rapidly. Novel technologies in modelling and simulation of these systems, including data-driven methods as developed in the civilian sector, allow the systematic development, testing and demonstration of these technologies for integrated hybrid propulsion and hybrid power system. Moreover, various components developed and tested at dislocated physical test-facilities at various scales can be tested, demonstrated, and validated in a combined digital twin and physical power hardware in the loop environment. This can provide the necessary steps towards implementation of the technology researched in the innovative propulsion call, for which industry currently prepare their proposals.

This approach allows to more rapidly pull-through commercially developed technology to military application for the following specific naval challenges:

• DC electrical power systems can be applied to reduce the number of conversion stages in electrical systems with increasing amounts of variable speed drives and high-power DC sensor and weapon systems. The growing need for electrical power requires a technological effort to increase the working voltage for DC shipboard grids. Moreover, novel DC power systems can increase the power system resilience by the application of fast acting power electronic based or hybrid switches and novel fault protection strategies.
• A modular, scalable hybrid propulsion and power system can enable the integration of diverse power sources such as dual fuel engines, gas turbines, fuel cells and batteries.
• For low and medium speed engine, technology is available for diesel methanol dual-fuel combustion engines. However, for power dense and silent high-speed engines dual-fuel combustion engines still need to be developed, tested, and integrated, with a specific focus on establishing the optimal operating point for efficiency, signatures, and its response to dynamic loads.
• While fuel cells are introduced in special maritime applications, like submarines or Autonomous Unmanned Vehicle demonstrators, the harsh dynamic loading, necessary reformer and shock requirements of surface vessels require specific design and integration changes for military applications and test and demonstration in an integrated hybrid power system.
• The integration of batteries can provide an energy source to provide power to highly dynamic loads, provide a back-up power source for power source failures and achieve a very silent low speed purely battery-electric operation.
• The integration of both low-flash-point fuels and energy dense battery systems requires specific integrated safety solutions to prevent fires and limit the impact of potential incidents, with a specific focus on military application.

This call topic contributes to the STEP objectives, as defined in STEP Regulation, in the target investment area of clean technologies.

Proposals must develop of a joint digital simulation environment using the knowledge gained from the civilian sector and several commercial national and EU research programmes. In addition, the proposal must develop a methodology to utilise various dislocated test facilities across Europa to evaluate the component behaviour (subsystems/components de-risking) and improve its system integration and control with a specific focus on military performance criteria such as autonomy at sea, survivability and minimal noise, infrared, electromagnetic and radar-cross-section signatures.

Moreover, the proposal must develop, prototype and demonstrate an integrated DC power system architecture with its fault protection, control strategies and components, with a focus on energy efficiency and military signature requirements. Furthermore, the proposal must also develop, prototype and demonstrate power sources, such as high-speed dual-fuel combustion engines, gas turbines on sustainable fuels, fuel cells and batteries.

In addition, proposals may address the development of AI controllers based on physical models to optimise the behaviour of the DC architecture in terms of energy and fuel consumption and GHG emissions reduction, with the focus on military requirements on safety and operation.

Types of activities

The following types of activities are eligible for this topic:

Accordingly, the proposals must cover at least the following tasks as part of mandatory activities:

• Studies:
  • Conduct research studies on novel concepts for propulsion and energy systems in future military vessels, with a focus on improving all functional requirements. In addition, the proposed studies should be justified and benchmarked against established functional requirements for military ships of similar size and mission profile.
  • Study, investigate and recommend possible standardised DC-grid Low Voltage (LV) and High Voltage (HV) power quality requirements that should facilitate the use of commercial and military equipment (HV and LV as defined by IEC).
  • Study and simulate the DC-grid behaviour in various fault conditions in order to establish the system power quality envelope, such as arc flash, selectivity, grounding faults.
  • Study and investigate possible LV-/HV- shore connection system, DC-AC and DC-DC.
  • Studies on the Low Voltage (LV) and High Voltage (HV)-DC-grid response to peak energy demands caused by e.g., direct energy weapons, high energy lasers.
  • Studies on the power quality and fluctuations in the Low Voltage (LV) and High Voltage (HV)-DC-grid during peaks of energy demands.
  • Study and demonstrate the various concept for alternative fuels / energy systems for Navy vessels, taking into account multinational operations including replenishment at sea operations.
  • Simulate and demonstrate the different energy conversion methods.
  • Simulate and demonstrate the difference in the energy conversion methods taking into account signatures, ramping up speed, exhaust gasses and fuel consumption.
  • Study and analyse the logistic support chain of alternative fuel / energy system challenges.
  • Analyse the environmental impact/possible benefits via a (comparative) Life Cycle Assessment.
  • Study and investigate new strategies and technology for energy monitoring and energy optimisation onboard military ships.
  • Study the integration of a robust and silence gearbox in the hybrid propulsion system taking into account increased military performance, energy density of the complete system and optimal speed selection.
• Design:
  • Adapt and demonstrate power sources for military purposes.
  • Develop innovative designs for complete propulsion and energy systems tailored to military vessels with different mission profiles, focusing on improving all functional requirements for future naval vessels of different sizes. In addition, the proposed designs should be fully justified and benchmarked against established functional requirements for military ships of similar size and mission profile, to ensure a robust and optimised solution.
  • Investigate dual/multi fuel high speed diesel engines utilising alternate sustainable fuels.
  • Design and demonstrate novel power dense converter technology, based on novel SiC based electronic components.
  • Design and demonstrate novel DC system architectures (MW-scale) and its fault protection strategy using both converter based and hybrid mechanical and power electronic switches.
  • Design and demonstrate advanced control strategies for fuel, emission, and signature optimisation.
  • Design and demonstrate integrated power system architectures and its power hardware in the loop development and testing strategy.
  • Design and demonstrate a redundant architecture LV/HV DC-grid systems based upon novel technologies.
  • Design, validate and demonstrate digital twins for propulsion and power systems with validation from test facilities and real vessels.
  • Design of a testbed for systems that have large HV DC request, such as direct energy weapons, etc.., which allows obtaining information about the DC-grid response and the elasticity of the grid.

In addition, the proposals should cover the following tasks:

• Generating knowledge:
  • For all components, identify criticalities regarding materials’ supply and study mitigation measures (including but not limited to substitutes – explaining potential limitations, circular management of components and recycling).
  • Investigate DC LV/HV ground faults, and their effects on ship corrosion including the impressed current cathodic protection system.
  • Investigate and recommend philosophy and "best practice" design for monitoring of DC LV/HV ground faults.
  • Investigate "best practise" philosophy, design and trade-offs with ground faults, EMC filters and ship corrosion for DC grid systems.
  • Investigate personnel safety for LV/HV DC grid.
  • Investigate the hazards imposed by the proposed alternative fuels and give the best practise design for a navy ship.
  • Investigate the possibility to define the DC-grid fault condition using a dependable design based on dynamic modelling (fault-forecasting based on dynamic simulations)
• Integrating knowledge:
  • Gain knowledge of the power layer and data layer integration in complex onboard DC power systems and control architectures in order to increase resilience.

The proposals may also cover the following tasks:

• Generating knowledge:
  • Develop, prototype and demonstrate for study purposes the integration of super-capacitors and/or flywheels, in combination with batteries, in order to combine the advantages of each of the technologies and improve the global power system efficiency.
• Integrating knowledge:
• Gain knowledge of the risks in the cyber domain (cyber-security tests) in order to define the vulnerability of the system architecture.

Proposals must substantiate synergies and complementarity with foreseen, ongoing or completed activities performed in the civilian sector and several commercial national and EU research programmes.

Functional requirements

The proposed product and technologies should meet the following functional requirements:

The technologies to be developed should focus on the following environmental and military requirements and its trade-off for both peacetime and wartime operating scenarios:

• Impact on all performance criteria listed below for top speed, cruise speed, and several peacetime and wartime typical mission profiles.
• Acceleration and deceleration behaviour of the propulsion plant in various mechanical, electrical, and combined operating modes.
• Weight and volume reduction of components and the integrated propulsion and power system.
• Noise signatures at various operating modes and for several peacetime and wartime mission profiles.
• Infrared signatures at various operating modes and for several peacetime and wartime mission profiles.
• Electromagnetic signatures at various operating modes and for several peacetime and wartime mission profiles.
• Radar Cross Section, which is directly related to size and displacement.
• Safety of alternative fuels, fuel cells and batteries, whether integrated alone or combined in a vessel, and the response to calamities caused either by internal failure or external damage.
• Range and autonomy (sea endurance).
• All exhaust gasses at all mission profiles (e.g., top speed, cruise speed in various operating modes and during several peace- and wartime typical scenarios).
• Integration of energy conversion system in combination with selective catalytic reduction systems.
• Energy efficiency at all mission profiles (e.g., top speed, cruise speed in various operating modes and during several peace- and wartime typical scenarios).
• Life Cycle Cost based on maintenance, fuel cost and manning for several peacetime and wartime typical mission profiles.
• Shock resistance, propulsion and power system robustness and resilience.
• Manning requirement for operation and maintenance.
• Modularity to enable both the application of the developed technology to a wide range of different platforms and future upgrades to further increase energy efficiency and improve military performance.
• Expected life limit for components and systems.
• Expected removal from ship / main overhaul for components and systems.
• Expected failure rates of components and systems (Mean Time Between Failure (MTBF) and Mean Time To Repair (MTTR)).

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