The Department Of Energy may have to find a new home in a few years time. An urban planning report produced by the National Capital Planning Commission looked at ways to improve the federal land of the National Mall so that it would become more 'liveable and sustainable' and the Forrestal Building, which houses DOE, might be one of the buildings to get the wrecking ball treatment.
The building was built in the 1970s and wouldn't look out of place in post WWII East Germany. But aesthetics aside, there are a few practical reasons why the building might have to go. From the article:
Unlike many buildings in Washington, D.C., Forrestal apparently doesn't have any grand historical or architectural significance. In fact, it makes kind of an odd home for the Department of Energy because it's notably energy inefficient (even though a cool roof and some other add-ons in recent years have helped a little). You also have to wonder about the security of a building that houses the National Nuclear Security Administration and yet has a street (10th Street) that runs directly underneath the structure. That has to be a security concern. Of course this is all still in brainstorming mode and no specific plans have been announced. The various government representatives involved gave very little comment, but the director of physical planning for the NCPC did provide some helpful context in the source article.