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Distributed Online Generalized Nash Equilibrium
Tracking for Prosumer Energy Trading Games
Yongkai Xie, Zhaojian Wang, John Z.F. Pang, Bo Yang, and Xinping Guan
Abstract—With the proliferation of distributed generations,
traditional passive consumers in distribution networks are evolv-
ing into “prosumers”, which can both produce and consume
energy. Energy trading with the main grid or between prosumers
is inevitable if the energy surplus and shortage exist. To this
end, this paper investigates the peer-to-peer (P2P) energy trading
market, which is formulated as a generalized Nash game. We
first prove the existence and uniqueness of the generalized Nash
equilibrium (GNE). Then, an distributed online algorithm is
proposed to track the GNE in the time-varying environment.
Its regret is proved to be bounded by a sublinear function of
learning time, which indicates that the online algorithm has an
acceptable accuracy in practice. Finally, numerical results with
six microgrids validate the performance of the algorithm.
Index Terms—Generalized Nash equilibrium, online optimiza-
tion, time-varying game, P2P energy trading market.
I. INTRODUCTION
The explosive growth of distributed generation in distri-
bution networks together with the advancement of commu-
nication and control technology at the consumer level have
gradually transformed the traditionally passive consumers into
“prosumers”, which can both produce and consume energy [1].
Then, energy trading with the main grid or between prosumers
is inevitable since energy surplus and shortage are bound to
exist [2]. In this situation, the peer-to-peer (P2P) market, which
operates in a distributed manner, is more popular due to the
ever-increasing number of prosumers, in which the various
prosumers can be self-organized to operate economically and
reliably under a given market mechanism [3]. In addition,
the increasing penetration and an aggravating volatility of
renewable generation calls for online market clearing methods.
In this paper, we intend to investigate the distributed online
energy trading market for prosumers.
For such P2P energy trading markets, they are usually
formulated as generalized Nash games, where each prosumer
maximizes its profit with coupling constraints, e.g., global
power balance [1], [2], [4]–[7]. Then, clearing the resulting
This work was supported by the National Natural Science Foundation
of China (No. 62103265), and the “Chenguang Program” supported by
the Shanghai Education Development Foundation and Shanghai Municipal
Education Commission of China (20CG11). (Corresponding author: Zhaojian
Wang)
Y. Xie, Z. Wang, B. Yang, and X. Guan are with the Key Laboratory of
System Control, and Information Processing, Ministry of Education of China,
Department of Automation, Shanghai Jiao Tong University, Shanghai 200240,
China, (email:wangzhaojian@sjtu.edu.cn).
J.Z.F. Pang is with the Institute of High Performance Com-
puting (IHPC), A*STAR, Singapore 138632, Singapore, (email:
john_pang@ihpc.a-star.edu.sg).
P2P market corresponds to finding the generalized Nash equi-
librium (GNE) of the energy trading game. For example, in [1],
the energy sharing game among prosumers is formulated with
full information, and [2] further designs a fully distributed
algorithm based on Nesterov’s methods to seek the GNE
with only partial-decision information. In [4], a P2P energy
market is formulated as a generalized Nash game, where the
prosumers who share payments are mutually coupled and
influenced. Following this, [5] and [6] further consider system-
level grid constraints. Lastly, in [7], a P2P energy market of
prosumers is formulated as a generalized aggregative game
with global coupling constraints. The aforementioned works
have made great progress in the distributed GNE seeking for
the P2P energy trading market. However, they usually focus on
only one time section and provide offline solutions to solve the
game. Due to the volatility of renewable generations and the
complexity of load profiles, both current and future operation
status changes much more over time, requiring much faster
algorithms, i.e., online GNE tracking.
In this paper, we formulate a P2P energy trading market
among prosumers in the distribution network and propose a
distributed online algorithm to track the GNE of the market.
The major contributions are as follows.
•A P2P energy trading market is modeled as a generalized
Nash game with both individual and coupled time-varying
constraints. Moreover, we prove the uniqueness of the
GNE of this market at any time section.
•A novel distributed online algorithm is proposed to track
the GNE, where each prosumer can make decisions only
using local variables and neighboring information. This
reduces the communication burden and makes it easier to
implement in practice.
•We prove a sublinear regret bound, i.e., that the regret of
the online algorithm can be bounded by a sublinear func-
tion of learning time, indicating that the online algorithm
suffers minimal “loss in hindsight”.
The rest of this paper is organized as follows. In Section
II, the P2P energy trading game is formulated. Section III in-
troduces and analyzes the performance of a distributed online
algorithm to track the GNE of the game in a time-varying
environment. Numerical results are presented in Section IV to
verify the effectiveness of our algorithm. Finally, Section V
concludes the paper.
Notations: In this paper, Rn
+is the n-dimensional (nonpos-
itive) Euclidean space. For a column vector x∈Rn(matrix
Am×n∈Rm×n), its transpose is denoted by xT(AT). For a
matrix A,[A]i,j stands for the entry in the i-th row and j-th
arXiv:2210.02323v1 [math.OC] 5 Oct 2022