Case Study: Landmark Net-Zero Building

5 min read

An inside look at Seattle's 303 Battery development.

303 Battery. Image courtesy of Sustainable Living Innovations

The address of what’s said to be the world’s most sustainable, net zero high-rise apartment property seems particularly fitting. Seattle’s 303 Battery will be solar powered, of course. But when need be, it also will be run on batteries.

It’s all part of the developer’s proprietary approach to construction. The technology-enabled system features factory-built panels that are manufactured with the wiring, plumbing and mechanical equipment pre-installed. Once the 112-unit, 15-story structure’s sub-basement and foundation are complete, the panels will be transported to the site and hoisted into place.

Indeed, even though the ground breaking was in June, 95 percent of the panels are finished and waiting in Sustainable Living Innovations’ Tacoma factory. And as a result, the building should be ready for occupancy next summer, far faster than projects of a similar size and scope. About 30 percent faster, according to the company.

About 900 panels will be used to erect the building as it rises in Seattle’s Belltown neighborhood. But there will be just 10 different types, including a specialized one for elevator shafts.

The project’s story goes beyond panelized construction, though. It also includes a host of sustainable features, such as the aforementioned solar panels. And with 27 of the units set aside for low and moderate income residents, there’s an affordability aspect, too.

The building has been pre-sold to Equity Residential, which focuses on the acquisition, development and management of rental properties located in urban and high density suburban markets. The company, which owns or invests in 307 properties—nearly 80,000 units—will take ownership upon the building’s completion.

Maximizing Energy

To maximize energy production, solar will not only be on the roof at 303 Battery, but also along two exterior walls and balconies. All the panels are designed and built in house, and a bank of lithium batteries in the basement will store the solar-generated power for use at night and when the sun is not shining.

While the solar panels and batteries were purchased from outside vendors, the approach to construction is home grown.

“You might say it has been 13 years in the making,” SLI CEO Arlan Collins told MHN. In trying to solve problems associated with high-rise construction and environmental performance, the company’s mantra is “half the time, half the energy and half the water,” he added.

According to the Department of Energy, buildings account for 40 percent of all greenhouse gas emissions in the United States. In Seattle, they’re responsible for about a third of the city’s greenhouse emissions. But 303 Battery will not be part of that problem, said Collins.

SLI believes energy usage in the building will be 70 percent less than a similar structure built conventionally, and will use “close to 50 percent” less water.

In that regard, rainwater will be captured and gray water will be reclaimed. The latter will be diverted from showers, washing machines and bathrooms and piped into the basement. There, a heat exchanger will extract heat from the water and put it back into the hot water tank. Consequently, the captured heat will never leave the building.

Because excess power can not be returned to the grid in this part of Seattle, the batteries will provide 192kw hours of storage, enough to run the building “for a couple of days,” Collins said. “It won’t take any energy from the grid.” The batteries will be housed in six refrigerator-size cabinets.

Elsewhere, daylight censors will reduce power needs throughout the structure, and elevators will be equipped with regenerative gears.

“Our proprietary technology, construction process, sustainable materials and smart-living technologies give (residents) a beautiful, comfortable home that produces no greenhouse gas emissions,” he said.

Meeting the Standards

Individual apartments in the structure will feature floor-to-ceiling glass walls that open to private balconies, radiant in-floor heating, quiet acoustics and such “top-tier” smart home features as app-controlled blinds, thermostats, lighting and locks. The company developed its own technology and software to help residents monitor their daily, monthly and annual energy and water use, and to see how they compare anonymously with others in the building.

SLI, a 60-employee firm which set out to build 303 as the most technological and energy efficient high-rise apartment buildings in the world, is seeking Petal Certification for the property from the International Living Future Institute, a global nonprofit working to inspire the greenest buildings for a healthy world. The certification includes incorporating urban agriculture, achieving a net-positive energy balance and prioritizing resident education and engagement with building and its systems.

“303 Battery shows that even high-rise apartment buildings can seek the world’s most rigorous standard for net zero energy,” said Margaret Montgomery, a Institute board member. “By emphasizing energy efficiency, avoiding fossil fuels, and relying on solar power, the project will create a path for others to follow.”

Washington Gov. Jay Inslee also praised the project, calling it both “a miracle of sustainability” and a “revolutionary approach to building.”  SLI is showing that “we can both address climate change and build up our economy,” the governor said, suggesting that the homegrown company’s systems could change the built environment across the nation.

Meanwhile, the 27 unit-set-aside is aimed at addressing the same affordability crisis that’s faced in nearly every city and town across the country. Three will satisfy Seattle’s Mandatory Housing Affordability requirements, while the other 24 will be income and/or rent restricted as part of the Multi-Family Tax Exemption program.

Collins said Equity Residential won’t be setting rental rates until shortly before leasing begins sometime next spring. The three MHA units will be leased to residents earning no more than 60 percent of the area median income; the other 24 affordable apartments will be leased to those earning no more than 80 percent of the AMI.

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