Chance-Constrained Energy Storage Pricing for Social Welfare Maximization
Ning Qi, Ningkun Zheng, Bolun Xu
TL;DR
The paper tackles pricing energy storage under uncertainty by formulating a two-stage chance-constrained economic dispatch aimed at social welfare maximization. It derives deterministic reformulations and proves key properties: the storage opportunity price $\theta_t$ is convex in SoC and increases with net-load uncertainty, while being linearly coupled to energy and reserve prices and bounded to regulate market power. Theoretical results are complemented by an 8-zone ISO-NE case study showing substantial reductions in electricity payments and system costs when using the proposed pricing framework, relative to profit-maximizing benchmarks. The approach yields operator-ready default bids and a principled benchmark for monitoring storage market power, with strong scalability as renewables and storage capacity grow.
Abstract
This paper proposes a novel framework to price energy storage in economic dispatch with a social welfare maximization objective. This framework can be utilized by power system operators to generate default bids for storage or to benchmark market power in bids submitted by storage participants. We derive a theoretical framework based on a two-stage chance-constrained formulation which systematically incorporates system balance constraints and uncertainty considerations. We present tractable reformulations for the joint chance constraints. Analytical results show that the storage opportunity cost is convex and increases with greater net load uncertainty. We also show that the storage opportunity prices are bounded and are linearly coupled with future energy and reserve prices. We demonstrate the effectiveness of the proposed approach on an ISO-NE test system and compare it with a price-taker storage profit-maximizing bidding model. Simulation results show that the proposed market design reduces electricity payments by an average of 17.4% and system costs by 3.9% while reducing storage's profit margins, and these reductions scale up with the renewable and storage capacity.
