We develop and exploit numerical models to address environmental issues associated with offshore renewable energy. These models address marine hydrodynamics (circulation, turbulence, bottom stress) and biogeochemistry (carbon cycle, nutrient and oxygen dynamics, primary production, eutrophication). They are typically applied in tridimensional and multi-annual contexts, at spatial scales spanning from a single wind farm to the entire North Sea basin. Recent research projects involves both wind and solar energy infrastructures.