Quick scan interactive effects heat plumes

This report presents a quick-scan assessment of the potential interaction between thermal plumes from offshore hydrogen production and hydrodynamic changes caused by offshore wind farms, focusing on a 450 MW hydrogen production case within the Ten Noorden van de Waddeneilanden (TNW) wind energy area in the Dutch North Sea. Using existing model results from the HyOne and Wozep studies, the analysis shows that thermal plumes from hydrogen production are highly localized, remaining confined to the immediate vicinity of the production platforms and exhibiting clear seasonal behavior, with limited spatial extent and small temperature increases, especially compared to wind-farm-induced effects. In contrast, offshore wind farms cause hydrodynamic changes at a much larger spatial scale, notably by enhancing vertical mixing and reducing stratification in summer, which can significantly influence primary production patterns. Visual and qualitative comparison suggests that interactions between thermal plumes and wind-farm-induced mixing are weak, partly compensating, and not additive, leading to a low to moderate ecological risk for the assessed scenario. However, substantial uncertainties remain, particularly regarding long-term effects, cumulative impacts, and future upscaling of hydrogen production, indicating the need for targeted follow-up research and adaptive monitoring to support responsible development.