583,000 square feet / 54,000 square meters
Iberdrola is the first tower in Europe to achieve LEED Platinum certification, the U.S. Green Building Council’s highest rating in sustainable design. The elegant 41-story glass tower is the focal point of Bilbao’s Abandoibarra development.
The tower anchors a new plaza, the Plaza Euskadi, on one of the city’s most important avenues, near the Nervión River. The tower’s graceful triangular form is derived from three segments of a cylinder tilted gently toward one another. In plan, the shape resembles a chevron, but with one side, the back, shorter. The two longer sides form a prow that points down the diagonal Elkano Avenue into the city, a gesture that is amplified by a sculptural glass and steel base. The light-filled multi-story lobby is finished in warm, honey-colored wood and stone.
To achieve the LEED Platinum rating, a wide array of environmental sustainability strategies was used. The concrete from an existing train yard was reused and fly ash was specified for the structural concrete. A continuous loop of 30°C (86°F) water runs through the building to assist in heating or cooling demands, depending on the season and time of day. Most significantly, the Torre Iberdrola has a highly efficient double-wall glass façade. Cool interior air circulates through the cavity between the walls, drawing heat up and into the ceiling plenum, allowing the building to recapture heat from its exposed areas and delivering it to where the demand is highest. Potable water consumption is reduced by 40 percent over that of a conventional building by using highly efficient fixtures, minimizing the irrigation, and implementing a system for filtration and reuse of gray-water.