The zero building: an exemplary nearly zero energy office building (NZEB) and its potential to become a positive energy building (PEB)

European energy policies introduced nearly zero energy building (NZEB) design to stimulate the energy transition in buildings, and EU programmes promote the evolution towards positive energy buildings (PEB). Most studies into NZEBs are based on simulations, and not on real monitoring data. This paper presents the real performance data of the Zero building, an NZEB office building with Leed Gold and Breeam Excellent environmental design certifications located in a neighbourhood that shares a zero-emission district heating-cooling facility relying only on 100% renewable energy sources. The current performance of the building and its neighbourhood is assessed to identify the existing gap to reach the goals of positive energy buildings (PEB). A study showed that it achieved a degree of self-sufficiency of 74.3% for the operational electric energy and that its carbon footprint is only 3.35 kgCO(2)/m(2)y, 92% lower than in a typical office building in locations with the same climate.