Balancing California's Grid Without Batteries

Neil Cammardella, Joel Mathias, Matthew Kiener, Ana Busic, Sean Meyn
2018 2018 IEEE Conference on Decision and Control (CDC)  
Demand dispatch refers to a collection of distributed control techniques to obtain grid services from flexible loads. A carefully designed control architecture can enable a collection of loads to behave in aggregate as a large virtual storage device. Grid-level ancillary services can be provided with minimal communication, while guaranteeing quality of service to the consumer. This work expands on prior work in several directions: • A natural notion of energy capacity is proposed for the
more » ... osed for the special case of thermostatically controlled loads (TCLs). It is shown that this quantity is closely approximated by thermal energy capacity, which is a component of the "leaky battery model" introduced in prior work. • Simulation experiments in a distributed control setting show that these energy limits, and accompanying power capacity limits, are reliable indicators of online capacity, even for a heterogeneous population of loads. • A feedforward/feedback control scheme is proposed for a large collection of heterogeneous loads. At the local level, control loops are used to create cooperative responses from each load in a given class of homogeneous loads. This simplifies control of the aggregate based on two pieces of information: aggregate power consumption from each class of loads and the state of charge surrogate that is a part of the leaky battery model. This information is required at a slow time-scale (say, 5 minute sampling). • The paper concludes with economic implications. In particular, given that dispatchable loads are a form of virtual storage and not virtual generation, it is not surprising that the use of real time or time-of-use pricing has been problematic.
doi:10.1109/cdc.2018.8618975 dblp:conf/cdc/CammardellaMKBM18 fatcat:srcleq35hbhjnc2apeyiihg2ky