This dual graduation project includes an architectural design for a sustainable building that houses the United Nations Environmental Council, within the urban context of the current UN site on Manhattan. The buildings contains a mixed programme of functions: the environmental council, auditoriums, offices and exposition space. This design is founded on a research on zero energy utility buildings, which serves a twofold purpose. Firstly to develop a generic design methodology for zero energy utility buildings that can accelerate the transition towards zero energy buildings. Secondly to develop a specific energy concept and energy balance for the integration of sustainable solutions into the design of the ‘United Nations Environmental Council’, founded on model based calculations.