One of Calgary's premier energy companies, EnCana Corp., has finally unveiled designs for a new downtown headquarters.

The Bow — whose name is drawn from the nearby Bow River and from the tower's curving shape — will be 59 storeys high and have an area of 1.7 million square feet.

This architect's rendering shows what EnCana Corp.'s new head office would look like on Calgary's skyline.

The glass and steel building will dominate the city's downtown skyline and will be the largest building in the country west of Toronto, according to Calgary Economic Development.

The tallest skyscraper in the country is First Canadian Place in Toronto, at 72 storeys, while the CN Tower soars 553.33 metres high, about 181 storeys.

"I think this project symbolizes the westerly shift of our economic power that's occurring in Canada today," said the organization's president, Bruce Graham.

The Bow, shown in this architect's rendering, will be 59 storeys high and have an area of 1.7 million square feet.

The $1 billion project, which includes indoor gardens and energy-conserving design features, will be located near Sixth Avenue and Centre Street.

"The form of the tower was really generated by a desire to try and maximize on the amount of perimeter, to try and give as many people a room with a view," said lead architect Nigel Dancey of Foster and Partners, based in London.

Randy Eresman, EnCana's president, said in a statement that the tower "will enhance staff recruitment and retention while creating an energetic urban village in our city's core."

"Our people will enjoy multiple advantages by being housed in a single location along with amenities such as indoor gardens, a public outdoor space, complementary retail businesses and vibrant cultural venues."

The Bow will encompass the York Hotel, which will be renovated into retail space, and the Regis Hotel, which will become a boutique hotel.

Calgary Mayor Dave Bronconnier called the project the keystone to the redevelopment of the long struggling downtown east end.

Construction of the tower will likely begin in the summer of 2007 and be ready for Encana's staff to move in by 2011.