OffshoreGrid will develop a science-based view on an offshore grid in Northern Europe along with a suited regulatory framework considering technical, economic, policy and regulatory aspects. OffshoreGrid is targeted for European policy makers, industry, transmission system operators and regulators. The geographical scope is first the regions around the Baltic and North Sea, English Channel and the Irish Sea. In a second phase, the results will be applied to the Mediterranean region in qualitative terms. In the preparatory phase, scenarios have been developed as input for the modelling work. Amongst others, these included scenarios for wind power generation, electricity demand and generation, planned grid development, technology developments,etc. The first modelling phase compared the costs and benefits of different offshore grid scenarios, focusing on the evaluation of offshore wind power hubs and on the combination with interconnectors. In the second phase, extra scenarios are calculated to further detail conclusions, and an evaluation will be done of how the overall European offshore grid could look like. In last instance, results are translated to the Mediteranean situation.