In Edmonton, a once-in-a-generation opportunity has presented a pressing question: Can a massive, carbon-neutral development rebrand a city and turn around decades of habitual sprawl?
The city unveiled ambitious plans on Tuesday to turn its defunct city-centre airport into a bustling collection of residences and stores. It's a green project unprecedented in Canada for its size, scale and proximity to the downtown core.
Five proposals by international design firms are being considered. All include plans for about 30,000 residents, retail and park space, light-rail transit and renewable energy sources.
Former airports offer a rare clean slate for a city to execute such a plan. Similar redevelopments are under way in Denver and Austin, while Montreal's far-flung Mirabel airport has also been considered for overhaul.
Edmonton is looking for its own silver bullet - a mixed-use, multibillion-dollar development to attract people looking to live in a green community while meeting demands of a growing population.
"This is a game-changer for our city, in terms of looking at the environment," said Councillor Kim Krushell, whose ward includes the old airport.
But it's a tall order. The project will take more than two decades, some doubt the power of one development to redefine the city's brand, and it dashes the hopes of some Edmonton business leaders who had wanted the historic site - Canada's first municipal airport - to stay in operation. (The city now relies on its international airport, which sits far to the south.)
The city has full control over the development because it owns the land. Council rejected earlier plans that weren't ambitious enough.
The funding model is complex and will depend on which proposal is chosen. Phil Sande, the city's executive director of the redevelopment project, said it "will be profitable for the city and its citizens" and boost quality of life in the downtown.
There's no comparable swath of prime, development-ready land in Canada. The site is slightly bigger than Toronto's Downsview Airport and 15 times the size of a similar redevelopment in Ottawa, at Lansdowne Park.
The project is a few kilometres north of the proposed site of a new hockey arena, which will anchor a $1-billion downtown entertainment and retail complex.
"That's the beauty of this - not many cities have 600 acres to play with four kilometres from downtown. And we do," Ms. Krushell said, adding: "People don't always think of Alberta and think 'green' - especially out east - and this is exactly that."
Officials hope to choose a proposal this year, break ground by 2014, open the first homes by 2018, and finish the project in 25 years.
The proposed developments are largely medium-density walk-ups and apartments. It's a far cry from what Edmonton is accustomed to - just over half of the city's dwellings are single-family homes (about twice the rate of Toronto or Vancouver).
Ulf Ranhagen, a chief architect with Swedish-based firm Sweco, one of the five finalists, said he's confident buyers will feel like they still have their own plot to call home. City officials are banking on it.
"This is, more than anything, a chance to redefine our housing market," said councillor Don Iveson.
Now, the question is whether existing residents or new ones (the city's population is growing) will snap up the units when they begin to sell.
"If they don't, God help us," laughs Mr. Iveson. "We've got a lot riding on this."
Most of the five proposals include a mix of renewable energy options.
Geothermal heating is being proposed for the development itself, but also on a scale that could heat nearby buildings in Edmonton's downtown. One proposal includes a greenhouse garden that would use excess heat from surrounding buildings.
Many of the proposals have factored in solar panels. A plan by U.S. architecture firm BNIM angles the roofs of all the housing to maximize sunlight exposure for solar panels.
The Sweco proposal also includes wind turbines and a bio-fuel plant that would convert waste to energy.
Most propose a mix of sources that could combine to exceed the power demand of the development itself, and add to the grid - one firm predicted it could generate 500 gigawatt hours over 20 years.
All but one of the proposals suggest some form of lake or canal in the area, which is currently a desolate mix of runways, hangars and a terminal.
These waterways would serve a function, a substitute for storm drains and a place to capture run-off water. One design suggests a waterway for canoeing and rowing.
Water will be recycled throughout the development, but water use will also be minimized - one proposal recommends special toilets that divert urine directly.
The city is banking on the development as a marketing tool, but professionals say it won't have a strong, focused effect such as that of Toronto's CN Tower or Sydney's opera house.
"From a branding point of view, I don't see it... being able to transform a city's image," said Adam Finn, a University of Alberta marketing professor. "They're all small things that are hard to present."