Europe is moving towards more sustainable, decentral and digital energy grids. Cities face the task of coordinating the local transition of renewable energy generation and storage, while maintaining grid stability. Integration between energy vectors (heat, electricity) is necessary to enable wider flexibility and improved efficiency. The North Sea Region (NSR) is leading the way, as many novel technologies and business models have been successfully demonstrated. But as the region prepares the transition, new challenges related to governance, finance and technology choices arise.AC/DC aims to deliver 25% reduction of CO2 emissions, 30% reduction of smart grid project development time and 20% of costs.No single organisation has the expertise or ability to experiment with a broad range of technologies, governance and financing models. To achieve these objectives, local authorities Eemnes (NL), West-Suffolk Councils (UK), Malmö (SE) and Mechelen (BE) will jointly explore and demonstrate how scaled approaches could be achieved. Examples include local energy community hubs, peer-to-peer energy trading models, and local collaborative planning tools. Support from 4 knowledge partners (Aarhus University, Johannesberg Science Park, IfM ECS, VITO) will provide expertise and structure. Together, this will result in a systematic upscaling approach, that delivers pathways and action plans to enable the energy grids transition, transferable to other authorities in the region.