Decentralized elastic electricity demand scheduling

Abstract

The adoption of intermittent renewables in the electricity grid will increasingly require loads to track available generation. This paper proposes several algorithms to schedule flexible-power loads that arrive unpredictably to a grid-connected microgrid. These are based on standard schedulers such as Shortest Remaining Processing Time (SRPT), adapted to the fact that appliances have maximum power ratings. A simple decentralized scheduler is applied to ensure that the aggregate load does not exceed the generation, and a gain control mechanism is proposed to stabilize the system. The proposed scheduler has two sources of sub-optimality: determining the values of the control signals, and their overall structures. In order to separate these two effects, we consider a full communication version as a benchmark in order to assess performance against the SRPT-based algorithms and fair sharing. This full communication “decentralized” approach approximates the performance of SRPT-based policies, suggesting that a true decentralized controller may be feasible in the future.