The Minnesota Twins unveiled the first sustainable field-irrigation system, as the team announced in conjunction with Pentair a custom-designed Rain Water Recycle System (RWRS) that will capture, conserve and reuse rain water at Target Field. Pentair’s RWRS is estimated to reduce the need for municipal water at Target Field by over 50 percent, helping the ballpark to qualify for LEED certification and saving more than 2 million gallons of water annually.

An attempt to address two big issues facing the Tacoma Dome -- budget deficits and inefficient energy consumption -- fell through when Tacoma Power turned down a naming-rights offer from the city worth some $1.25 million over five years. Tacoma Power is a regulated utility, and officials felt it was a poor use of the firm's limited marketing budget.

In Minnesota, arenas in St. Cloud, Paynesville, Austin and five other cities already use geothermal refrigeration systems to good effect. They'll be joined by a two-rink complex, the Burnsville Ice Arena, by October 2010 if all goes well.

In an arena geothermal refrigeration, the temperature-tempering qualities of the Earth are accessed. The temperature below the frost line is relatively constant, around 50 degrees. Loops of tubes are placed deep under the frost line, and a mixture of coolant and water is circulated. A heat pump extracts the heat, leaving behind a coolant cold enough to create ice for the arena.