By Evan Dick & Nadav Malin
Photovoltaic solar arrays like this one on the Living Buildings Challenge-certified Hawai’i Preparatory Academy Energy Lab will be essential to most projects seeking Net Zero Energy Building Challenge certification. Wind and geothermal energy sources are also acceptable for NZEBC; no combustion-based power generation is allowed.
The International Living Future Institute (ILFI), owner of the Living Building Challenge, is going where no certification program has gone before with a new Net Zero Energy Building Certification program. Jason McLennan, chief executive officer of ILFI, sees this program as a response to environmental constraints that a growing human population is facing on an already stressed planet.
Many projects are claiming net-zero-energy status, often based on modeling with little documentation to verify their performance post-occupancy. McLennan told
that ILFI has received many inquiries about a net-zero-energy certification. “The market needed someone to step up and provide some clarity. People are making claims about net-zero, and anytime you have claims without certification, it’s not a good thing,” he said.
The Net Zero Certification is an offshoot of Living Building Challenge that requires projects to achieve five of the 20 imperatives of Living Building certification—Limits to Growth, Net Zero Energy, Rights to Nature, Beauty + Spirit, and Inspiration + Education. Net Zero Certification, like Living Building Challenge, relies on 12 months of detailed post-occupancy performance data to prove that annual energy usage is actually equal to or less than energy production.
The Net Zero Energy imperative prohibits combustion of any kind as an energy source, including any use of onsite biomass such as wood chips or cordwood. This constraint has been controversial for some Living Building Challenge projects, and principal group manager Paul Torcellini of the National Renewable Energy Lab (NREL), who has authored numerous studies on zero-energy buildings, questions whether it’s the right move. If you don’t allow combustion, Torcellini argues, you’re relying on the utility grid’s energy storage capacity, and that storage is primarily in the form of stockpiled coal. In response, McLennan points out that combustion, even of wood, is polluting and transportation-intensive. “Pushing for true net zero without combustion pushes people towards much greater efficiency, better envelopes, and a more rigorous commissioning process. It results in better, more efficient buildings that are much healthier to be in as well,” McLennan says.
Torcellini also suggests that additional rules would help account for building loads. “In order to get to zero, people are doing whatever it takes to reduce loads,” he says. “That could mean outsourcing the data-center to an off-site facility—should that be allowed?” Similarly, in the Living Building Challenge, wastewater has to be treated on the site, creating an additional energy load. Without that imperative, the Net Zero Certification isn’t quite as demanding, even on energy, as Living Building Challenge.
This rendering of a soon to be constructed building designed to achieve LBC certification at the the University of Wollongong’s Sustainable Buildings Research Centre in New South Wales, Australia demonstrates renewable energy features that will be common on projects vying for the new NZEBC certification.
The other included imperatives make this new certification program very different than any other effort to codify zero-energy building performance. The Limits to Growth imperative recognizes that perpetuating sprawling development will offset gains from a net-zero-energy building. The Rights to Nature imperative ensures that buildings won’t achieve net-zero energy at the expense of neighboring buildings through excessive shading. And the Beauty + Spirit and Education + Inspiration imperatives are intended to promote the inclusion of renewable energy systems in ways that are attractive and inspiring. “We want these projects to be beautiful and well designed,” says McLennan.
As in Living Building Challenge, exemptions will still be allowed for certain situations and materials considerations, provided that teams demonstrate due diligence by proving the need for the exemption and, where possible, document their advocacy for change in zoning ordinances and materials supply-chain practices. “If there are alternatives that comply, we won’t let someone use a material on the red list,” McLennan clarified.
Will ILFI start offering other sub-certifications? A net-zero-water certification could conceivably be broken off from Living Building Challenge, as has been done with energy. McLennan didn’t speculate, telling
, “It’s a good question. A lot of things are possible; what we do next remains to be seen.”
For now, ILFI is hopeful that Net Zero Energy Building Certification will encourage projects to engage with Living Building Challenge. “We’re very excited about the program, and we got lots of interest [in October 2011] at Greenbuild,” says McLennan. “We hope that those who seek this sustainable path—and who are successful—will capitalize on the possibilities and consider expanding their scope to achieve full Living Building Challenge certification in the future.”
For more information:
International Living Future Institute
November 1, 2011