A net zero-energy community (ZEC) is one that has greatly reduced energy needs through efficiency gains such that the balance of energy for vehicles, thermal, and electrical energy within the community is met by renewable energy. Past work resulted in a common zero-energy building (ZEB) definition system of “zero energy” and a classification system for ZEBs based on the renewable energy sources used by a building. This paper begins with a focus solely on buildings and expands the concept to define a zero-energy community, applying the ZEB hierarchical renewable classification system to the concept of community. A community that offsets all of its energy use from renewables available within the community’s built environment and unusable brownfield sites is at the top of the ZEC classification system at a ZEC of A. (A brownfield site is where the redevelopment or reuse may be complicated by the presence or potential presence of a hazardous substance, pollutant or contaminant.) A community that achieves a ZEC definition primarily through the purchase of new off-site, Renewable Energy Certificates (RECs) is placed at the lowest end of the ZEC classification but is still considered a good achievement.
NREL/TP-7A2-46065
