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A pilot project is underway in New Brunswick, Canada, to demonstrate direct control of thermostatically controlled loads as a means of providing ancillary services. This paper will focus on one of the load classes, aggregated control of domestic electric water heaters (DEWHs) as a means of shifting load profiles. The approach not only strives to satisfy utility level objectives by curtailing individual DEWHs in a strategic manner but also takes account of the thermal dynamics of individual heaters and estimates of hot water usage in an attempt to maintain customer comfort and satisfaction. The aggregated load controller is unique in its topology and operation, consisting of an individual load extractor, a water demand model, and a temperature estimator for each DEWH, together with a reserve capacity forecast unit and aggregated load control logic. Details of the aggregated load controller are developed, the relationship to the system operator is described and a summary of preliminary results is provided.