Zero Energy Buildings Gaining Ground
Zero energy commercial buildings are cropping up across the United States according to a report released earlier this year by the New Buildings Institute (NBI) and the Zero Energy Commercial Building Consortium (CBC). Zero energy buildings are efficient buildings that produce as much energy as they use through on-site renewable energy resources.
This report, “Getting To Zero 2012 Status Update: A First Look at the Costs and Features of Zero Energy Commercial Buildings” is the most comprehensive look at the state of zero energy commercial buildings to date. It examines the number, location, costs, and design strategies of various types of zero energy commercial buildings (ZEBs) as well as zero energy-capable (ZEC) buildings. The ZEC buildings are energy efficient enough to be zero energy, but have not taken the final step of on-site renewable generation.
The report identifies 99 buildings that are either zero energy, ZEBs, or ZECs currently under construction or recently completed with limited performance data. It finds that the number and diversity of commercial ZEBs and ZECs are growing and can be found in most climate zones. The technologies as well as design and construction practices used to create these buildings are readily available in today's market.
While in the past, ZEBs were primarily small, “demonstration” buildings, these projects are expanding in size and building type. Among the innovative buildings capturing the attention of architects and builders are the IDeAs Z2 Design Facility in San Jose, CA; Hudson Valley Clean Energy Headquarters in Rhinebeck, NY; and Richardsville Elementary School in Bowling Green, KY.
Key report findings include:
- ZEBs have been successfully built in most climate zones of the United States.
- The majority of ZEBs to date are small or very small buildings, however there are increasing examples of larger and more complex buildings. Many of the earliest examples are academic buildings or environmental centers, in effect, demonstration buildings sometimes with low occupancy levels. More recent buildings include office buildings, K-8 schools and a credit union; buildings that represent large numbers of “average” or typical buildings.
- ZEBs are constructed using readily available technology. An integrated design approach with careful attention to building site and layout, envelope, mechanical systems, and electrical systems is critical to achieve the high levels of energy efficiency. Unique or experimental systems are infrequently used to reach net zero goals, but the emergence of new technologies will be a factor in the expansion to more building types.
- Modeling studies indicate costs of 3% to 18% for energy efficiency features, depending on building type, size, climate, and other variables. Reported incremental costs are only available from a few ZEB projects making conclusions or trends difficult to derive from the limited information available. However, the few reported ZEBs appear to show lower overall incremental costs than modeled estimates, possibly due to positive tradeoffs with other features in the design and construction process. Those costs range from 0% to 10%.
The report also summarizes recommendations that would encourage additional development of ZEBs such as:
- practical guidance for the commercial building community including 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.
NBI is a nonprofit organization working collaboratively with commercial building professionals and the energy industry to promote better building energy performance. CBC members include over 450 commercial building stakeholders committed to charting a path for achieving net-zero energy commercial buildings. The National Association of State Energy Officials (NASEO) serves as the secretariat for the CBC and also co-sponsored the study.
A copy of the full report and additional information on ZEBs can be found on NBI’s website.
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