A cost/benefit analysis of full interconnection of customer-owned standby generators.
Joshua Meyer is a manager in Encorp’s Business Development group. John Farls is a technical advisor for Encorp. Dennis Troester is the Midwest regional sales manager for Encorp. Authors’ Note: Certain figures and illustrations for this white paper were obtained from the consulting firm of Arthur D. Little. Encorp has sponsored Arthur D. Little’s research and has noted the portions of this paper that are derived from Arthur D. Little’s work.
Synchronous interconnection of small generators with utility power distribution systems offers energy managers the potential to increase electric power reliability and to reduce overall energy costs. In selecting interconnection technologies, energy managers are faced with investment risk as they are challenged to define and deliver the additional benefits associated with closed transition transfer systems. Traditionally, small generators have been installed with an open transition transfer system that creates a physical barrier between the generator and the utility distribution network. In contrast, a closed transition transfer system maintains a fluid link between the utility network with the generator. This article explores the interconnection applications and illustrates the economic impact of interconnecting a backup generator with a utility-owned power system from the energy manager's perspective.
Interconnection of a small generator with the utility grid provides benefits unavailable through isolated installations, including those with automatic transfer systems. A closed transition transfer system linking the customer-owned generator and the utility-owned power distribution network is the most cost effective means available to create full interconnection. Closed transition transfer systems enable synchronous or parallel operations with the utility grid in overlap type transfers, soft loading type transfers, or continuous parallel operations. Synchronous operations enable seamless transfers of load between the utility and the generator. Interconnection benefits include improved power reliability and power quality, enhanced peak shaving capabilities, performance testing under normal operating conditions, and the ability seamlessly to dispatch the generator for economic purposes.