Standby power generation under utility curtailment contract agreements

Many electric utilities in the United States offer large industrial and commercial customers power sales contracts which have attractive rates under a curtailment requirement. This curtailment requirement allows the utility to require the customer to reduce its power demand to a predetermined level within a specific time period. This paper reviews the alternatives faced by a curtailment contract customer together with potential load shedding and standby generation system designs. An example of implementing a curtailment contract at an existing industrial facility is presented. The example facility, Boeing and Helicopters of Philadelphia, Pennsylvania, USA, required both load shedding and standby generation. The load shedding scheme is fairly complex and is controlled by a programmable logic controller (PLC). The standby generation and load shedding systems for the example facility are examined in detail. Also, lessons learned from implementing the required modifications to the example facility are discussed.