This report is the first in a series that will focus on building control system (BCS) technology trends, emphasizing the impact of emerging technologies on energy management systems and products. The purpose of this series is to provide energy practitioners in the Federal sector with basic informational tools to assist decision making relative to energy management systems design, specification, procurement, and energy savings potential. This report provides an overview of the factors affecting the development of BCS technology and outlines BCS potential in the federal sector. Other reports will concentrate on three areas: BCS networking technology [1], product offerings, and applications software.