Hannaford Supermarkets says its new store in Augusta, Maine – the first to earn a top award for environmentally friendly construction – will be a laboratory of sorts. Opening Saturday, it’s the nation’s first to achieve the U.S. Green Building Council’s highest platinum standard.Part of the roof is covered with drought-resistant plants to impede water runoff and provide insulation. It draws power from a solar photovoltaic system, called Maine’s largest. Supports for a walkway are recycled from an old airport hangar. Natural daylight is utilized, and water from two geothermal wells helps regulate the building’s temperature. Hannaford design services Director Fred Conlogue said Wednesday the building is a “learning laboratory” whose green advancements may be used in other stores.