Analyzing the Role of the DSO in Electricity Trading of VPPs via a Stackelberg Game Model
Peng Wang, Xi Zhang, Luis Badesa
TL;DR
The paper analyzes the role of a Distribution System Operator (DSO) as a trading organizer for Virtual Power Plants (VPPs) using a Stackelberg bilevel model, where the upper-level DSO maximizes profit and the lower-level VPPs minimize operating costs. The lower level is replaced by its KKT conditions to yield a single-level MPEC, solved with BilevelJuMP.jl and SCIP.jl to obtain a Stackelberg equilibrium. Results show that DSO-mediated trading (Mode 2) reduces energy flows to the wholesale market and lowers VPP costs, while allowing the DSO to capture profits, highlighting regulatory concerns about market fairness. The findings emphasize implications for market design, illustrating how an intermediary DSO can coordinate internal trading to benefit itself and VPPs, but potentially at the expense of wholesale-market revenues; future work should extend to ancillary services and formal proofs of equilibrium properties.
Abstract
The increasing penetration of distributed energy resources has sparked interests in participating in power markets. Here, we consider two settings where Virtual Power Plants (VPPs) with some flexible resources participate in the electricity trading, either directly in the wholesale electricity market, or interfaced by the Distribution System Operator (DSO) who is the transaction organizer. In order to study the role of DSO as a stakeholder, a Stackelberg game is represented via a bi-level model: the DSO maximizes profits at the upper level, while the VPPs minimize operating costs at the lower level. To solve this problem, the Karush-Kuhn-Tucker conditions of lower level is deduced to achieve a single-level problem. The results show that the role of the DSO as an intermediary agent leads to a decrease in operating costs of the VPPs by organizing lower-level trading, while making a profit for itself. However, this result comes with interests loss of the wholesale market, implying that stakeholders in the market need to abide by regulatory constraints.
