Washington Post: Hundreds of District homeowners signed up for free household energy audits last year through the D.C. Department of the Environment — some hoping to cut their utility bills, some to be “greener” and some because it was free. But this month, instead of the energy assessments they were promised, more than 100 homeowners received letters saying that liens had been filed on their property because the city never paid a contractor for doing the work. Patuxent Environmental Group …