Construction is scheduled to begin in about a year and be finished 18 months later on a planned 70 to 100-ft-tall net-zero-energy use building in Portland that would, if completed, rank as the tallest net-zero-energy-use building in the U.S. The team for the $40-million Oregon Sustainability Center, which includes SERA Architects, GBD Architects and general contractor Skanska USA, is beginning a 12-week feasibility phase. Design should start in February. The seven-to-nine-story structure would be the tallest ever proposed for ranking by the Living Building Challenge, a certification program for completed buildings with net-zero energy and water use and net-zero carbon emissions. LBC is administered by the International Living Building Institute, an advocacy group for sustainable design and construction that also develops performance-based standards. Some 70 projects have registered with the LBC but only three have received certification.