When district energy makes more sense than Living Buildings

Yellowknife, Canada.

Let me state right up front that I admire the Cascadia Green Building Council, and not just because they gave me a press pass to a thought provoking conference teeming with bright green luminaries in Vancouver last week.

As the South Bronx restoration hero Majora Carter put it last Wednesday, Cascadia is basically Apple to the U.S. Green Building Council’s PC – the independent regional chapter is hipper, bolder and closer to the leading edge of smart building.

Cascadia’s Living Building Challenge is especially visionary, I think, for promoting buildings that are ecologically helpful and restorative, rather than just trying to make our current methods less harmful. The deep-green standard requires that buildings capture and produce all of their own water and energy on site and that they avoid a red list of unhealthy materials.

But … my big reservation with the Living Building Challenge is the focus on individual buildings. Alex Steffen likes to say that there’s no such thing as a sustainable lifestyle; there are only sustainable societies. That is, you can’t extricate yourself from the system in which you live, no matter how many surge protectors you unplug. No man is an island.

By the same token, there may be no such thing as a sustainable building, only sustainable neighborhoods, cities and regions. An energy independent urban mid-rise only accomplishes so much if the buildings surrounding it are powered by coal. And district energy, a method of sending heat and water to clusters of buildings from centralized sources, may not lead to any one net-zero-energy and net-zero-water building. But it may still be more efficient.

So I was glad to see district energy get some attention at Cascadia’s Living Future conference. A session on the topic began with a list of advantages district energy can bring: greater resilience, flexibility in fuel types, avoided infrastructure costs, financial support from municipalities and what David Walsh of Sellen Sustainability called “thermal matchmaking.”

“One person’s excess [heat or steam] is another person’s need,” he said.

District systems typically aren’t huge – perhaps a few or a few dozen buildings. The business case, said Ken Morrison of Corix Utilities, comes not through economies of scale but “economies of scope” – providing multiple services at once. Corix has helped set up natural gas, biomass, and waste-heat recovery systems on U.S. military bases in Alaska; at Victoria, B.C.’s Dockside Green housing development; at the University of Oklahoma in Norman; and at the Beaver Barracks affordable housing project in Ottawa, Ontario.

The most intriguing project described, though, is in the Canadian sub-arctic, some 1,000 miles north of Edmonton, Alberta. Mark Henry, community energy planner for the city of Yellowknife, explained the unique needs of the mining town of 18,000 that’s also the capital of the Northwest Territories. The town dates back to only the 1930s, Henry said – the average annual temperature of 25 degrees Fahrenheit kept most settlers away before that. The frigid climate also creates a sizeable energy need – the town spent $115 million on energy in 2004, most of that on space heating for buildings. There’s no natural gas, Henry said, so the town burns oil.

But, because it’s a mining town, Yellowknife is sitting on a huge potential heat source. “We have this massive thermal reservoir sitting below our community,” Henry said. The 80 kilometers of nearby tunnels, reaching 190 meters deep, have significantly higher temperatures than the surface. The town wants to tap that resource by connecting the mine heat to downtown buildings. It’s still selecting a private partner to design, build and operate the system. Henry expects to see it built out by 2018.

An interconnected system like that probably makes more sense than living buildings would in the remote community. It’s good to see that Cascadia understands the value of district solutions and gave them some billing last week.