This article analyses legal aspects of the Swedish wind power development, theoretically based on how different types of knowledge are represented in legal contexts, mainly in the courts. A sample of appealed wind power permits is analysed, a handful of relevant informants are interviewed - including two judges in the Land and Environment Court and the appeal court - and the legal setting is analysed. Of key interest here is the interplay between expert and lay statements in the court cases, which here is related to the concepts of calculating and communicative rationalities that are developed in the planning literature. The results indicate that the juridification - which takes place as a permit issue is appealed in the judiciary system - supports the calculating rationality more than the communicative, and that the plaintiffs often attempt to adapt in how they shape their argumentation.