Using Residential AC Load Control in Grid Operations: PG&E's Ancillary Service Pilot

This paper summarizes the results from a PG&E pilot designed to assess the ability to use air conditioner direct load control to provide ancillary services. The study included nearly 2000 residential households with control devices that were instructed to cause an immediate and complete shutdown of the air conditioner compressor 71 times over a two and half month period. It summarizes the start and total ramp time of AC load response, the magnitude of the response, the effect of the curtailments on customer comfort and satisfaction, and the approach to providing near real time visibility of the air conditioner electricity demand.