How Much Energy Is There in Historic Buildings?

            As Richard Moe explains, “embodied energy” refers to the concept that buildings represent—embody—the energy needed to manufacture or extract building materials, to transport them to a construction site, and to assemble them into a building. If the building is demolished and its materials dumped in a landfill, the energy that they embody is seen as going into the landfill as well.

In the full version of his speech, Moe cites statistics about the amount of energy embodied in historic buildings and the amount of time that it would take for a new building to make up the difference by its more efficient operation. Among other things, he says, “Recent research indicates that even if 40% of the materials are recycled, it takes approximately 65 years for a green, energy-efficient new office building to recover the energy lost in demolishing an existing building.”

A number of preservationists and environmentalists have questioned these figures. They believe that the catch-up time is much shorter—although the concept of conserving embodied energy remains important to saving resources. As the discussion continues, the National Trust hopes to host a symposium of experts to try to get a more accurate sense of the energy embodied in buildings.