Green at City Scale

Over the past decade, green building has moved out of the fringe and into the mainstream. LEED Gold and Platinum buildings are becoming commonplace in both public and private buildings. Now Portland, Oregon, is going one step further. As part of an evolving "eco-district" policy, city leaders aim to move beyond the design of individual structures to focus on greening entire neighborhoods. The idea is to pool resources among buildings to reduce greenhouse gas emissions and improve energy- and water-use efficiency.

"Green buildings are pretty far along, but if you really want green cities, you have to look at whole systems," says Eric Ridenour, an associate with SERA Architects. Ridenour is under contract with the city of Portland to develop an eco-district plan for Portland State University, one of two pilot projects targeted for development next year. The second is the Lloyd Crossing neighborhood, a residential and business corridor across the Willamette River from downtown.

At first glance, the eco-district framework, outlined in an eight-page city document, reads like a rehash of Sustainability 101: yet another plan to create green jobs, encourage smart growth and catalyze renewable energy development. A closer look reveals plenty of innovation, but the novelty is driven by economies of scale and integration of existing systems--not cutting-edge green technologies.

One strategy is to build district heating projects: centralized heating plants that pipe hot water via underground pipe to multiple buildings at the same time. Community-based thermal systems, which are ubiquitous in Scandinavia, eliminate the need to install--and pay for--chillers and boilers in individual buildings. According to the International District Energy Association, they also are about 20 percent more efficient than conventional approaches, and transition easily to renewable fuels such as biomass.

Another proposal involves coordinating rainwater reuse strategies, so that runoff from one building can be reused in a neighboring structure. At Portland State, for example, runoff generated by a large classroom and administrative building could be reused as greywater supply to toilets in a dormitory, Ridenour says.

Portland isn't the only city scaling up its green-building practices. Seattle is hatching a plan for "climate benefit districts," which would integrate energy and public transportation solutions to reduce greenhouse-gas emissions in a given neighborhood. In China, an "Eco Block" prototype is planned for the city of Qingdao. The design includes multiple residential towers and townhouses and calls for reusing all of the community's water, recycling 80 percent of its waste and reducing energy demand by 40 percent.

Of course, all of these projects depend on good business models to get off the ground. As the Portland planning process moves forward, the city is looking at creating incentives for developers who sign on to an eco-district. Branding will be a key part of that effort, says Ridenour, adding that eco-districts do more than address collective environmental impacts. They also are good marketing tools, he says. "People want to live in green neighborhoods."