[1] Ecofys Germany, D-10785 Berlin, Germany
[2] Ecofys Netherlands, NL-3503 RK Utrecht, Netherlands
[3] Ernst & Young & Associes, F-92576 Neuilly Sur Seine, France
[4] Vienna Univ Technol, Inst Power Syst & Energy Econ, Energy Econ Grp, A-1040 Vienna, Austria
[5] Fraunhofer Inst Syst & Innovat Res, D-76139 Karlsruhe, Germany