U.S. Dept. of Energy, Nov. 16, 2016.
http://energy.gov/eere/articles/energy-department-announces-partnerships-under-new-better-buildings-zero-energy

"...today the U.S. Department of Energy (DOE) and the National League of Cities launched the Better Buildings Zero Energy Districts Accelerator to move the building market toward adopting sustainable practices to help districts achieve zero energy use in buildings. Zero Energy Districts are comprised of multi-purpose energy-efficient buildings, where the annual energy delivered to buildings is less than or equal to on-site renewable exported energy."