In Focus: Net Zero Buildings

12 April of 2012 by

net zero label In Focus: Net Zero Buildings

When we hit the economic downturn of the late 2000s, electric usage declined in most developed regions such as Europe, Japan, and the U.S. One of the big debates in today’s electric business is what to expect for future load growth. Historically, electric usage has been closely tied to economic growth and lifestyle gains. As gross domestic product grows, so does electric usage, and people’s lives are assumed to be better off. So the assumption is that as economic activity picks up, so will electric demand. But lately, forecasters have questioned whether it is time to reconsider that assumption.

NetZerograph2 In Focus: Net Zero Buildings

The Concept of Net Zero Buildings
What factors could break the link between economic growth and energy usage? One is a shift  from a more intensive electric use from industrial activity to a less intensive use from the services sector. The second is a shift to a more efficient use of electricity. One area with significant potential for more efficient use is the building sector. Indeed, it is now not only possible but in some cases economically practicable to build homes and businesses with net zero energy use. What does net zero mean? Simply that the building produces at least as much energy as it consumes. There are two steps to accomplishing this goal:

  1. Incorporate as much energy efficiency into the building as possible so that the energy needed to attain expected comfort levels is as low as possible.
  2. Incorporate renewable energy so that the building produces energy as well as consuming it.

Net Zero is Being Done Today
The question by most people when they first hear of this concept is “Isn’t this really expensive?” Innovative builders are proving it doesn’t have to be. The developer New Town recently built a $424,000 net-zero home in Denver, Colorado. The developer’s price is $26,900 higher than the same home without net-zero features [1]. Considering that a typical energy bill in Colorado is more than $200/month and that the incremental amount financed in a 30-year mortgage would only cost about $130/month at current interest rates, it actually might be cost beneficial to go with the net-zero option assuming financing is available.

The concept is now moving from individual homes to whole neighborhoods. University of California – Davis is now building West Village, which will be the largest net-zero energy community in the U.S. with the intention of demonstrating that the concept of net zero is practicable on a large scale [2]. The first phase of the project was completed in 2011 when about 800 students, faculty, and staff moved into new apartments. Using the principles of net-zero construction, energy efficiency was designed into the buildings from Day One. Features include solar reflective roofing; radiant barrier roof sheathing; extra insulation; high-efficiency lighting, air-conditioning, and appliances; roof overhangs; and window sunshades. The buildings use approximately 50% of the energy that would be utilized if they had been constructed to California’s current building codes (which are some of the strictest in the nation from the standpoint of requiring energy efficiency). To achieve the net-zero goal, the development contracted with solar developer SunPower to install a 4 MW photovoltaic solar system.

Sunlight reflects off the metal window sun shields on the Ramble apartments at West Village at UC Davis in Davis, CA. (Photo by Greg Urquiaga/UC Davis)

Can Net Zero Be Extended to Commercial Buildings?
So if net-zero buildings are feasible for residential construction, are they also feasible for commercial buildings? California certainly thinks so.  The California Public Utilities Commission (CPUC) established a strategic energy plan in 2008 that included strategies to make all new residential construction in the state   net-zero by 2020 and  all new commercial construction net-zero by 2030. Rather than just sitting back after releasing these optimistic strategies, the state developed specific action plans through a collaborative process called Engage 360 [3]. The task force already lists a number of successful net-zero commercial buildings in California including IDeAs Z Squared Design Facility in SanJose, Audubon Center at Debs Park in Los Angeles, the Challengers Tennis Club in Los Angeles, the Environmental Technology Center in Rohnert Park, and Packard Foundation Headquarters in Los Altos. Elsewhere, large net-zero commercial buildings have been built or are being planned including the Oregon Sustainability Center in Portland, Oregon [4], which will begin construction in late 2012; National Renewable Energy Lab buildings in Golden, Colorado [5], completed in 2010 and 2011; the Elithis Tower in Dijon, France, which makes the claim to be the world’s first energy-positive office tower [6]; and the National Institute of Environmental Research building in Incheon, South Korea, which claims not only to be net-zero energy but also to be net-zero carbon [7].

The Research Support Facility (RSF) in Golden, Colorado, is NREL’s
newest sustainable green building and was completed in October 2011.
(Photo courtesy of NREL’s Photographic Information Exchange).


What Impact Could Net Zero Have?
It will take time and many more successful projects before net-zero buildings can prove themselves as the prevailing paradigm, but the current research and knowledge being gained opens the door for a potential future of dramatically lower net energy usage by residential and commercial buildings.  The Rocky Mountain Institute suggests by 2050 the average building could use ½ to ¾ less energy than today [8]. What impact might this have on the overall energy picture?  Studies show that over 40% of the energy consumed in the U.S. is consumed by residential and commercial buildings. So, if Net Zero allows us to reduce demand by 50%, we would drop our energy consumption by 20%. This scenario introduces a whole new concept: economic growth coupled with reductions in energy usage.

By Bob Shively, Enerdynamics’ President and Lead Instructor

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