It makes good environmental sense because the green roof will cut down energy consumption at the arena -- at a time when arena management is looking at higher evergy bills. It's also a great demonstration for the viability of the green roof in a large civic project: it will be the largest green roof in the state of Minnesota and the only one on an NBA arena.

At a press conference yesterday, officials with Spurs Sports & Entertainment announced the changes, which came after a $190,000 grant from the San Antonio Water System.

After years of planning, several false starts and some unexpected lack of support from state officials, the new $80-million Duluth Entertainment Convention Center is on track for a December 31, 2010 opening date following more than two years of construction.

The complex's showcase will be a 6,600-seat arena slated to host home games for the University of Minnesota-Duluth hockey teams.

But what makes the arena notable is the emphasis on sustainability and green practices. Architects and designers say they're going for Leadership in Energy and Environmental Design (LEED) certification -- and if this is achieved, the new DECC arena will be one of the first in the United States to achieve such a designation.