In the past few years, net-zero buildings—those that produce as much (or more) clean energy on site as they use annually—have been gaining momentum. Once considered a crazy idea, they’re now coming of age as a realistic goal for a building. More than 400 such buildings are documented globally, with about one-fourth in the U.S. and Canada. This growing number is encouraging, yet for comparison, there are more buildings on the Cornell University campus alone than there are net-zero buildings worldwide. (RMI is currently developing plans for just such a building for its own use, high in Colorado’s mountains, and Amory Lovins expects his own house, which included RMI’s headquarters for its first 18 years, to go net zero as well.)
LESSONS FROM SINGULAR BUILDINGS
Shooting for net-zero status—whether it’s a realistically achievable goal or not—can galvanize creativity around a commendable, big, aggressive target. Recent projects illustrate five more key lessons for successfully reaching net-zero status for a building:
1. Double down on efficiency and plan for solar: In July 2013 the Packard Foundation announced results from the first year of operation of its headquarters building in Los Altos, CA. Extensive energy efficiency efforts reduced consumption to 46 percent below California’s strict Title 24 standards, at 351 MWh for the year. That allowed solar PV to shine and take the building right through the net-zero ceiling, producing 418 MWh.
2. Learn, then repeat, repeat, repeat: The first try is invariably more costly than it need be, so finding a way to repeat very similar efforts many times creates huge scaling opportunities. Walgreens, the largest drug store chain in the nation, opened its first net-zero retail store in Evanston, IL, in November 2013. In addition to myriad energy efficiency gains, the store features two wind turbines, 850 solar panels, and a geothermal heat pump system. Thomas Connolly, Walgreens vice president of facilities development, said, “We are investing in a net-zero energy store so we can bring what we learn to our other new and existing stores.”
3. Climate is not necessarily a barrier: Habitat for Humanity opened a new net-zero home in Minneapolis’s cold climate in December 2013. The building’s super-insulated building shell, triple-glazed windows, and R-100 ceiling insulation minimize energy use, while solar thermal and photovoltaic systems will provide more energy than the home consumes. Commercial housing developers like Shea Homes and De Young Properties have recently announced new offerings in multiple climate zones to test buyers’ interest.
4. Might makes right: Though most completed net-zero buildings are small (as are most new buildings of any kind), the success of net-zero buildings like the Bullitt Foundation’s new 52,000-square-foot building in Seattle, WA, and NREL’s recently completed 220,000-square-foot office building in Golden, CO, illustrates that a bigger building has more, not fewer, options for achieving net-zero status.
5. Pesky plug loads: Designing and building a potentially net-zero building is one thing, but a remaining challenge is the humans inside and their tendency to plug in gadgets, ranging from computer servers to coffee pots to computers and smartphones. The Packard Foundation building’s 67 MWh/y surplus was more than created by the nearly 90 MWh/y saved by RMI Senior Fellow Peter Rumsey’s push on plug loads, saving 58 percent of their energy compared to a normal Energy Star list but at no extra cost.
NET-ZERO LAW AND ORDER
With net-zero buildings now a reality, building codes, standards, and certifications are evolving as well. The federal government has remained a leader in this space, with Executive Order 13514, signed in October 2009, requiring all new federal buildings entering the planning process in or after 2020 to be net zero by 2030. The Byron Rodgers Federal Building in Denver, CO, is on its way to that status. And the U.S. Army Corps of Engineers has been piloting net-zero buildings since 2011. It aims by 2030 to spread net-zero-energy, -water, and -waste designs to its installations worldwide, with important projects underway from Fort Bliss, TX, to the U.S. Military Academy at West Point, NY.
Meanwhile, California’s revisions to Title 24 building standards establish ambitious new performance goals, requiring all new residential construction to be net-zero energy by 2020, and new commercial buildings by 2030. In addition, Governor Jerry Brown’s new executive order requires state agencies to take measures towards achieving net-zero energy for 50 percent of the total floor space of existing state buildings by 2025.
Another milestone was the Living Building Challenge’s 2012 introduction of a rigorous net-zero energy building certification standard.
CALCULATING NET ZERO AND LEVERAGING THE GRID
No key U.S. net-zero buildings could be net zero without the electric grid—utilities accept surplus solar power from these buildings during the day and provide them with power at night or on cloudy days. Net-zero buildings don’t typically operate fully off-grid, though many isolated older buildings have done so at extra cost with batteries.
Thus, net-zero and nearly-net-zero buildings present a challenge for utilities and regulators responsible for designing electricity rates. Under existing rate designs, net-zero buildings may pay nothing, or very little, for the services that electric utilities provide balancing the load. This is partly why California’s public utilities commission defined net-zero energy to mean that the net societal value of grid electricity consumed vs. on-site renewable energy generated is positive (as determined by some complex accounting).
Elsewhere, utilities and regulators in multiple jurisdictions around the country are also looking at how electricity prices can better reflect the cost of serving net-zero customers and provide incentives for net-zero-energy buildings to minimize potential costs to the grid. Eventually, this may include charging customers for how heavily they use the grid’s services at critical times, rather than just charging them for the amount of energy they use in a given period. Such changes could realign the incentives for net-zero design toward flattening their loads through better management of when energy is used, or perhaps through on-site storage.
TAPPING THE POWER OF COMMUNITIES
Going net zero one building at a time is a commendable goal, but as we’ve already begun to discuss, not without challenges, including accounting, the role of the utility, the potential for overbuild (sizing a single building’s renewable generation to cover its peak load), and practical challenges unique to particular buildings.
Enter the biggest growing trend for net-zero energy planning and design: net-zero districts, campuses, and even entire communities.
Applying net-zero energy at a district or community level has several advantages. For instance, multi-building systems offer opportunities for taking advantage of diverse load shapes, heat requirements, and opportunities for renewable energy production. Just as automakers can meld many models’ fuel economies into a fleet average, so too can net-zero districts and communities achieve net-zero status in aggregate even though some individual buildings may do better or worse.
So far, the nation’s largest planned community designed to reach net-zero energy is West Village, a mixed-use campus neighborhood at the University of California, Davis. It’s designed to ultimately house 3,000 students along with 500 staff and faculty families. The first phase is complete and has been occupied for more than a year, achieving 87 percent electrical self-sufficiency. Higher-than-expected demand from plug loads in some of the apartments, together with glitches in heat-pump water heater operations, accounted for the shortfall in meeting the net-zero goal in the first year, but West Village’s managers are confident that they will do it. Even the results to date are inspirational.
Such larger-scale net-zero efforts are taking place at RMI as well. Our collaboration with energy service company Ameresco and Arizona State University is aiming to propel the nation’s largest university to a net-zero carbon footprint—a tougher standard than net-zero energy—by 2025. It’s the most aggressive large campus project in the country. Meanwhile, the city of Fort Collins, Colorado, also with help from RMI, has undertaken the development of FortZED, a zero-energy district encompassing much of the city’s downtown business district and the Colorado State University campus.
MAKING NET-ZERO COMMUNITIES A REALITY
While the promise of net-zero communities is alluring, challenges remain. It may be easier in theory to design a net-zero district or community than to try to meet such a standard for each building individually, but it’s not always possible. Existing electric utility regulations, for example, typically forbid neighbors from exchanging energy among themselves, blocking integrated community microgrid solutions that could offer a net-zero pathway.
Yet RMI’s Electricity Innovation Lab (e-Lab) is working on that problem and others. In the end, opening the door to net-zero-energy communities could be a powerful way to enable the transition to a cleaner and more secure energy future.
James Newcomb and Robert “Hutch” Hutchinson are managing directors at RMI. Their article originally appeared on the Rocky Mountain Institute website and was reposted here with permission.
