Controllable Joint Forecast of Oversized Photovoltaic-Energy Storage Systems Considering Energy Storage Flexibility

Abstract

Coordinated operation of photovoltaic (PV) and energy storage (ES), which leverages ES flexibility to hedge against the uncertainty of PV, is a promising solution to facilitate the penetration and consumption of solar energy. In this paper, we focus on the emerging oversized PV-ES hybrid generation systems (HGSs) and propose the corresponding optimal declaring model. The generic model integrates scenario-oriented uncertainty modelling of PV output, operation strategy of PV-ES HGSs, and a bi-objective optimization model considering generation and penalty. Taking a PV-ES power station located in Northeast China as the case study, detailed comparisons between different weathers, ES capacities, and DC/AC ratios are carried out. The results show that: (1) The proposed operation strategy can be effectively applied to oversized PV power stations, which maximizes the consistency of actual operation results with the declared plan. (2) The optimal declaring model yields a range of solutions with different objective preferences, providing operators with a flexible and controllable decision space. (3) Diverse comparisons reveal the operation characteristics of PV-ES HGSs, including the existence condition of competition between objectives, and the impact of the objectives on operation. Thus, this work provides effective guidance for the design, operation, and joint forecast of oversized PV-ES HGSs.

Keywords: Photovoltaic-energy storage hybrid system, Coordinated optimal operation, Joint forecast, Energy storage flexibility