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.

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 behavior 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.