DC – AC/DC hybrid grid for a modular, resilient and high RES share grid development Proposals will address solutions for the design, modelling, simulation, development, demonstration, test and validation of new DC-based grid architecture(s) including a MV - LV DC - AC/DC hybrid grid architecture based on a DC underlay grid interconnecting micro/nano-grids. The modular grid planning and development, the “firewall” effect against faults or cyberattacks and the accommodation of higher shares of renewables in a DC-based system will be part of the demonstration and validation exercise.Different types of generation and loads, including RES, battery storage and electric vehicle (EV) will be part of the demonstrations, which will be tested in interconnected as well as in isolated mode. Each solution proposed has to be demonstrated in at least two Members States or Associated Countries. Each demonstration has to include at least two micro/nano-grids (AC or DC), of which at least one with low-voltage DC infrastructure. Each demonstration has to be interconnected with at least one point of common coupling (PCC) to the existing grid through medium-voltage DC.TRL will range between 5 and 8 (see part G of the General Annexes). Proposers will indicate the estimated levels of TRL at the beginning and at the end of the project.In addition to the demonstration activities, proposals should include a task on the identification of the barriers to innovation and market uptake of the proposed architectures (e.g. technical (including, low-cost DC breakers, WBG[[Wide Band Gap components]]), regulatory, standards, safety, acceptance and suitable business models) and pathways to overcome them (e.g. standardisation, such as of voltage levels), including recommendations.Proposals should foresee the coordination on policy relevant issues (e.g. regulatory framework, business models, data management, and consumer engagement) with similar EU-funded projects through the BRIDGE initiative[[http://www.h2020-bridge.eu/]]. An indicative budget share of at least 2% of the EU contribution is recommended for the research work associated with these issues and an additional 2% of the EU contribution for the coordination effort.The Commission considers that proposals requesting a contribution from the EU of approximately EUR 7 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts. The increase of renewable energy generation in the electricity grid necessary to meet the EU's decarbonisation objectives represents a complexity for the management of the electricity grid based on Alternating Current (AC). At the same time, cyberattacks are difficult to fight due to the real-time requirements, the cascading effects, and the coexistence of legacy and state of the art technologies within a digitalised electricity system with an increasing number of access points. Direct Current (DC)-based systems may provide a flexible, secure and reliable way forward. Many renewables generate in DC and much of the loads and equipment are already in DC. At the same time DC-based converters have become more efficient with the result that DC-based systems could be considered as viable solutions to tackle the aforementioned challenges.. The potential DC grid technologies for the development of the electricity grid thus need to be demonstrated, the barriers to be overcome identified and the business models for further exploitation developed. Exploiting these technologies will contribute to increasing European knowledge and leadership in these areas. The proposed solution(s) will contribute tofacilitating planning and targeting investments in the sector;increasing resilience of the electricity grid to faults and cyberattacks;increasing penetration of RES in the power network;increasing the efficiency of the electricity system.