Is New Building Ever Green?

"When Chevron moved across the lake last month, it vacated a 21-story office tower in downtown New Orleans that it spent a million dollars renovating after Hurricane Katrina. For all the sustainable flourishes of the new campus -- the walking paths, the reflective roof, the energy-efficient glass -- the company overlooked perhaps the greenest option of all when it decided not to adapt the building it already had.

"The greenest building is the one that's already built," said Patrice Frey, director of sustainability research for the National Trust for Historic Preservation. "There's a tremendous impact to the environment whenever you construct something new."

Buildings are suffused with what architects call embodied energy -- the fossil fuels consumed to harvest lumber, manufacture concrete, and assemble such materials into a finished product. The National Trust estimates that constructing a new 50,000-square-foot commercial building releases the same amount of carbon into the atmosphere as driving a car 2.8 million miles. Chevron's is six times that size.

It's a concept of special relevance in New Orleans, where public and private institutions have used Katrina as an opportunity to retire old but functional buildings and replace them with contemporary models better suited to the demands of the modern workplace. Charity Hospital, some public schools and the state offices near Duncan Plaza all face the prospect of disuse, or even demolition."