TY - CHAP U1 - Konferenzveröffentlichung A1 - Hennicke, Peter A1 - Thomas, Stefan A1 - Irrek, Wolfgang A1 - Zymla, Bernhard T1 - Towards sustainable energy systems : integrating renewable energy and energy efficiency is the key ; discussion paper for the international conference "Renewables 2004" Y1 - 2004 SP - 22 S1 - 22 PB - Wuppertal Institut für Klima, Umwelt, Energie for Climate, Environment, Energy CY - Wuppertal PB - Wuppertal Institut für Klima, Umwelt, Energie for Climate, Environment, Energy CY - Wuppertal ER -