Offer Curve Generation for the Energy Storage System as a Member of the Virtual Power Plant in the Day-Ahead Market

We build an offer curve for an energy storage system (ESS), which is a member of the virtual power plant (VPP) with photovoltaic (PV) modules and load. The offer curve should be built based on the optimal VPP operations while having many pairs of bidding prices and amounts in order to respond to unknown prices. Therefore, we propose the VPP operation strategy and predict the scenarios of DA electricity prices, PV outputs, and load separately by using three autoregressive models. Then, we build the offer curve for the ESS at each hour for 24 h by considering optimal VPP operations and three predicted scenarios. Finally, we verify the optimality of the VPP operation strategy by comparing it to a fixed-time strategy. We also compare the profit of our ESS offer curve to that resulting from a single offer.