1. School of Industrial Engineering and ManagementDepartment of Machine DesignKTH Royal Institute of TechnologySE‐10044StockholmSweden
2. Department of Energy and EnvironmentDivision of Electric Power EngineeringChalmers University of TechnologyS‐412 96GothenburgSweden
3. Fraunhofer Institute for Wind Energy and Energy System Technology IWESHannoverD‐30167Germany
4. Institute for Future Energy Consumer Needs and Behavior (FCN)School of Business and Economics/E.ON Energy Research CenterRWTH Aachen UniversityD‐52062AachenGermany