Strategic scheduling of energy storage for load serving entities in locational marginal pricing market

Abstract

Cost-effective approaches of storing electrical energy on a large-scale can help the grid operate flexibly and reliably. Public utility commissions view energy storage (ES) as a vital yet complementary part of other clean technologies such as renewable generation. As a coherent framework is being mapped out to increase the penetration of renewables in total electricity generation, load serving entities (LSEs) have been encouraged to procure ES systems to hedge against the intermittence and uncertainty of renewable power such as wind. Owing to the increasing penetration of wind generation, it becomes more complex for LSEs to obtain a deterministic ES scheduling decision, i.e. charging/discharging portfolio. To address this challenge, a bi-level strategic scheduling model is proposed in which the primary objective is to maximise the LSE’s profit by optimally scheduling ES charging/discharging profile. The sub-problem is Independent System Operator’s (ISO’s) economic dispatch for generation cost minimisation, assuming foreseeable impact in market-clearing price from ES. This bi-level model is converted to a stochastic mathematic programme with equilibrium constraints by recasting the lower-level problem as its Karush–Kuhn–Tucker optimality conditions. Numerical examples based on the PJM 5-bus and IEEE 118- bus systems are presented to demonstrate and validate the proposed approach.