We present CairnFORM, a shape-changing cylindrical display that physicalizes forecasts of renewable energy availability. CairnFORM aims at creating and encouraging new socially-shared practices by displaying energy data in collective and public spaces, such as public places and workplaces. It is 360˚-readable, and as a dynamic physical ring chart, it can change its cylindrical symmetry with quiet motion. We conducted two user studies. The first study clearly revealed the attractiveness of CairnFORM in a public place and its usability for a range task and for a compare task. Consequently, this makes CairnFORM useful to analyze renewable energy availability. The second study revealed that a non-constant motion speed is the better visualization stimulus at a workplace.