Steffen Haller has extensive experience in the energy sector, currently serving as Bereichsleiter Energieeffizienz at ENGIE Deutschland since July 2000, where responsibilities include overseeing energy efficiency activities across multiple locations including Berlin, Dresden, Frankfurt, Hamburg, Köln, München, and Stuttgart. Prior to this role, Steffen Haller held various positions at LTG Aktiengesellschaft from January 1996 to June 2000, including Niederlassungsleiter and Projektleiter for Energiespar-Contracting and Energiemanagement.