BACnet® technology enabled the City of Tucson to realize a goal to have an open and competitive energy management and control system (EMCS). For years, the City of Tucson was locked into a proprietary control system with no options for competitive bidding except to operate multiple, separate systems. The city did not want to continue enduring operation and maintenance problems associated with that setup. As the aging control system approached the end of its useful life, the city began to explore replacement options, which included the possibility of a BACnet solution.