There is a demand to remove CO2 from thermal plants to abate global warming. At the same time authorities demand treating wastewater to remove nitrogen and phosphorus and also to produce food. By combining algae farming at a power plant and using nutrients from the wastewater, actions to meet all these demands can be combined to a win-win situation. In this paper we make estimates what the dimensions and design criteria there would be for such an integrated system. The size of the algae farm will be significant. If placed in the sea, this may be feasible, but then storms must be considered. If we place in lakes, it is more competition for other uses that causes a problem. Combining with also greenhouses may be a possible solution. The biomass produced can be used directly as food or be processed by, e.g., fermentation to produce chemicals and methane (biogas). © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.