Zero-energy commercial buildings are both feasible and affordable, and they are appearing across the U.S., a report from the New Buildings Institute (NBI) and the Zero Energy Commercial Building Consortium (CBC) finds.
The report, Getting to Zero 2012 Status Update: A First Look at the Cost and Features of Zero Energy Commercial Buildings, defines zero-energy buildings as highly efficient structures that produce as much energy as they use through on-site renewable resource.
Altogether, the report identifies 99 existing and under-construction buildings that are either zero energy or zero energy-capable. These are spread through most U.S. climate zones. And while ZEBs were once considered the province of educational institutions and non-profits, the report found that recent zero-energy buildings include office buildings and a credit union.
The report identifies 21 occupied buildings with either measured net zero energy results (15 cases) or credible modeled expectations for such results (six cases). These are listed in the table above.
With the exception of two facilities completed in 2010 – Richardsville Elementary at 77,000 square feet and the NREL facility at 222,000 square feet – all ZEBs are less than 15,000 square feet, and half are less than 5,000 square feet, NBI said.
Interestingly, the study found that unique or experimental systems are infrequently used to reach net-zero goals. Most ZEBs are built using readily available technology. An integrated design approach with careful attention to building site and layout, envelope, mechanical systems, and electrical systems helps to achieve the highest level of energy efficiency, the report said.
On-site generation with solar PV panels is another common denominator among existing ZEBs, NBI said.
According to the report, the incremental costs for ZEB energy efficiency features range from 3 percent to 18 percent, depending on building type, size, climate and other variables.
As the larger office buildings market moves towards ZEB, minimizing electrical loads from plug-in equipment and appliances, along with other miscellaneous or “unregulated” loads, is a priority, the report said. The emergence of new technologies will also be a factor in the expansion to more building types, NBI said.
Other recommendations from NBI to encourage the development of ZEBs include guidance for the commercial building community, cost information for owners, increased measurement and communication of results on successful design strategies and technology applications, and better benchmarking to define expectations for performance of highly energy efficient buildings.