A novel scheme for randomized customer-sensitivity-based control of thermostatic loads for better integration of intermittent renewables

Increased electric grid penetration of intermittent renewable energy sources has reduced the controllability of the generation side, and created a need for more coordination between generation and load to maintain grid stability. Thermostatically controlled loads (TCLs) have long been seen as capable of providing a source of load flexibility. However, controlling thousands of small loads to create a better match between generation and consumption is a challenging task. Direct load control methods tend to be imprecise, invasive, and somewhat coercive, while pricing-based methods can result in social push-back and produce unreliable results. We propose and analyze a probabilistic control scheme based on a novel type of aggregator-customer contracts. The latter are tailored a priori so as to account for a customer’s particular tolerance to loss of comfort versus interest in cost reduction. While through these contracts, aggregators have to obey pre-agreed constraints on their controls, the up-side for them is that they can reliably anticipate the aggregate behaviors that their pool of loads can achieve. The control is decentralized via a single socalled pressure signal which is broadcasted and acts locally, in a probabilistic manner, on thermostat set-points. We demonstrate how the probabilistic nature of the control allows achieving a continuum of smooth potentially desirable aggregate load behaviors.