Gates Foundation HQ in Seattle the greenest

SEATTLE — The Gates Foundation says its headquarters campus in Seattle has been certified at the highest level of green buildings.

It says it's the largest nonprofit building in the world to achieve the Platinum certification for new construction in the Leadership in Energy and Environment Design program.

Green features include a solar energy system on the roof that provides more than a third of the hot water used and a 750,000 gallon water storage tank used in the cooling system.