Electric Power ›› 2026, Vol. 59 ›› Issue (2): 127-137.DOI: 10.11930/j.issn.1004-9649.202507063

• Power Market • Previous Articles     Next Articles

Equilibrium analysis of generator bidding in the electricity spot market considering medium- and long-term transactions

LI Xiaogang1(), LIU Qiyuan2(), FENG Yuanhao2(), WU Min1, CHEN Zhongyang1, FENG Donghan2()   

  1. 1. East China Branch of State Grid Corporation of China, Shanghai 200120, China
    2. Key Laboratory of Control of Power Transmission and Conversion of the Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2025-07-21 Revised:2025-10-17 Online:2026-03-04 Published:2026-02-28
  • Supported by:
    This work is supported by Science and Technology Project of East China Branch of SGCC (No.52992424000W).

Abstract:

To examine how medium- and long-term (MLT) market transactions affect spot-market operations and to analyze generators' bidding strategies in the spot market, this paper proposes a bilevel optimization model and a multi-agent deep reinforcement learning (MADRL) algorithm to simulate the bidding equilibrium of generators in the electricity spot market. A supply–demand ratio is introduced to characterize spot-market tightness, and the prospect theory is employed to capture generators' bounded-rational behavior, thereby analyzing the impact of MLT transactions on bidding strategies of generators in the spot market. In the MADRL solution process, generators are modeled as agents and market clearing is modeled as the environment; iterative training yields equilibrium bidding strategies for each generator and the corresponding spot-market clearing prices. A case study on an actual power system in Eastern China involving eight generators demonstrates that the proposed MADRL approach effectively computes generators' bidding strategies and accurately simulates the influence of different MLT market settings on spot-market operations. The findings provide quantitative guidance for power trading institutions to assess strategic bidding and to design coordinated rules for the joint operation of MLT and spot markets.

Key words: medium- and long-term market, spot market, bilevel model, equilibrium analysis, reinforcement learning