This paper will describe the concept of net zero energy (NZE) buildings and how the result of migrating to their large scale deployment will force the built environment to live within the energy budget provided by nature. This has long been one of the "Holy Grails" of the strong sustainability movement. In addition this paper will provide information on the growth of the photovoltaic industry supporting the deployment of NZE buildings, and discuss the state of the art of current U.S. residential and commercial NZE buildings.. Finally the barriers and problems with the NZE concept will be described to provide closure on this subject. The increasing cost of energy and international pressure to address climate change are forcing some major shifts in high performance building strategies in the U.S. and elsewhere around the world. Coupled with lower construction costs, tax breaks and other incentives, and more favorable pricing for renewable energy systems, particularly photovoltaics, the implementation of net-zero energy (NZE) strategies for commercial and residential construction is rapidly moving from concept to reality. Migrating to NZE buildings is being embedded in U.S. energy strategy and California has already mandated NZE residential buildings by 2020 and NZE commercial buildings by 2030. Importantly, the ability to set energy targets has stimulated thinking about how the "net-zero" concept can be extended to resources other than energy, here termed Net-Zero 6 (NZ6): energy, carbon, water, materials, waste, and land.
