Centennial Place, a new green building in Calgary.

When The Bow, a $1 billion office tower under construction in Calgary, is completed in 2011, the 58-story building will be the largest office tower in Canada outside of Toronto. Designed by London architecture firm, Norman Foster + Partners, The Bow—named for the river it overlooks—has an arc-shaped aerodynamic design to reduce the amount of steel needed for structural support, extra floor space for air circulation to help reduce heating and cooling costs, and a dazzling network of atriums and sky gardens. The green features are expected to reduce The Bow’s energy use by 33 percent compared with conventional buildings.

“In design, in sustainability, The Bow will be second to none,” says Michael Brown, associate vice president of Matthews Southwest, the developer behind the project. “There is nothing like it in Calgary.”

But if The Bow is intended to showcase a certain kind of 21st century urban innovation, its occupants are targeting decidedly 20th century business practices. The 1.7 million-square-foot skyscraper will be taken up entirely by EnCana, Canada’s largest oil and gas producer and a driving force behind the exploration of Alberta’s oil-rich tar sands. But can a city be at once the headquarters for the country’s petroleum industry and a leader in the development of sustainable building policies?

Black gold

With reserves six times the size of Saudi Arabia, Canada’s tar sands have triggered a modern-day black gold rush—and international condemnation from environmental groups.

In a report released last winter, Environmental Defense, a Canadian nonprofit, described the region’s tar sands oil project as “the most destructive project on earth.”