Earlier this week plans for the Bullitt Foundation’s Cascadia Center for Sustainable Design and Construction were presented to the City of Seattle’s Design Review Board, and the innovative project garnered front page attention from the Seattle Times. To be located at the corner of 15th Ave and Madison in the Central District, the Cascade Center is the first mid-rise building in Seattle to pursue the Living Building Challenge, a rigorous new “deep green” building standard developed by the Cascadia Chapter of the U.S. Green Building Council.
(rendering credit: Miller Hull)
The overarching philosophy of The Living Building Challenge is that a building should behave like an balanced organic system. Thus, for example, a Living Building should be able to function using only the amount of water that lands on its site as precipitation; it should generate as much energy as it uses; it should produce no waste; and it should also be beautiful.
Bullitt’s Cascadia Center is one of only two Seattle area projects that are currently targeting Living Building certification. The Restorative Design Collective is providing pro-bono design services for small one-story science building at the Bertschi School on Capitol Hill that is on track to be the first project in Washington State to meet the Living Building Challenge (or at least come close to it). Construction is scheduled to complete in November 2010.
But the Bullitt project—designed by Miller Hull and developed by Point32—takes it up a notch, literally, by attempting a much larger and taller building. And the greater the number of floors, the more challenging the Living Building Challenge becomes, in particular with respect to energy and water. That’s because the amounts of solar energy and precipitation available to the building are determined by the area of the site, and with more floors, those limited resource inputs have to be shared between more users and space (I’ll get back to this Catch22 below).
In Seattle, staying within the rainfall budget essentially comes down to incorporating a cistern that can store enough of the rain that falls in the wet season to meet water demand through the dry season. In an average Seattle year, about 225,000 gallons of rain hits the 10,000 square foot site. Highly efficient water fixtures and drought-tolerant plantings are a given.
While water conservation is destined to become more important over time, energy is a more pressing and challenging factor today. The goal is to achieve net zero energy, such that over a year as much energy is generated as is used. At certain times during the year the building might be using more than it is generating, and vice-versa, and that’s okay as long as annual net use is zero or less.
The basic strategy to achieve net zero energy involves applying efficiency measures to reduce the building’s energy use as much as possible, and then implementing on-site renewables to cover the remaining energy demand.
With the use of ground source heat pumps, heat recovery ventilation, solar hot water, passive cooling, daylighting, and a highly insulated envelope, along with an assumed 50 percent reduction in plug loads (stuff that gets plugged in to the wall by occupants), the designers project that the building will use only about one-third of the energy consumed by a baseline building that complies with Seattle’s energy code.
In urban Seattle, the only viable choice for renewables are photovotaic solar panels (PV), and the Bullitt project will be loaded up with them, as can be seen in the rendering below:
(rendering credit: Miller Hull)
According to Design Review package, the designers’ calcs are based on commercially available PV panels with efficiency roughly 50 percent higher than the industry standard. Even so, PV coverage on the building had to be maxed out on both the roof and the south facing facade to (hopefully) generate enough to hit net zero. And to squeeze every last bit out of it, the team requested a departure to allow the rooftop PVs to overhang beyond the property line.
The Bullitt PV system will be the largest in Seattle, snatching that honor away from High Point Center, which I wrote about here. The designers estimate it will produce in the range of 250,000 kWh of per year—enough to meet the energy needs of nearly twelve average Seattle households.
The net-zero energy approach of the Bullitt project is remarkably similar to the scheme applied to the Issaquah Net Zero Energy Homes. And the reality is none of it is rocket science. Many, if not all of these strategies could be implemented in every new building designed from this day on.
Even if the Bullitt project doesn’t achieve true net-zero energy use (or other Living Building Challenge goals) in practice, it is still hugely important as a trail blazer. As physicist and climate expert Joe Romm argues here, deployment of existing technology immediately is our best hope for achieving climate stability in the necessary time frame. We cannot afford to wait for energy miracles that may or may not come.
Lastly, as I noted above, because achieving net zero energy use becomes inherently more difficult as building heights increase, a net-zero requirement could potentially discourage tall buildings, which is not typically a desired outcome. For example, a net-zero single-family home is definitely not “greener” than say, a mid-rise multifamily building that only produces half of it’s own energy, because the higher residential density brings many other sustainability benefits. In fact, the Bullitt project, at six stories, is already pushing right up against the maximum number of floors for which net-zero energy is a practical possibility.
This is not to say nothing is gained by striving for goals like the Living Building Challenge or the 2030 Challenge. On the contrary, Bullitt’s Cascadia Center for Sustainable Design and Construction is exactly what we need to be doing a lot more of. The only embarrassing thing is how long it has taken Seattle bust a move and do it.
