*Article* **An Optimization Approach Considering User Utility for the PV-Storage Charging Station Planning Process**

**Yingxin Liu 1,\*, Houqi Dong 1, Shengyan Wang 1, Mengxin Lan 1, Ming Zeng 1, Shuo Zhang 1, Meng Yang <sup>2</sup> and Shuo Yin <sup>2</sup>**


Received: 28 November 2019; Accepted: 6 January 2020; Published: 8 January 2020

**Abstract:** Based on the comprehensive utilization of energy storage, photovoltaic power generation, and intelligent charging piles, photovoltaic (PV)-storage charging stations can provide green energy for electric vehicles (EVs), which can significantly improve the green level of the transportation industry. However, there are many challenges in the PV-storage charging station planning process, making it theoretically and practically significant to study approaches to planning. This paper promotes a bi-level optimization planning approach for PV-storage charging stations. First, taking PV-storage charging stations and EV users as the upper- and lower-level problems, respectively, during the planning process, a bi-level optimization model for PV-storage charging stations considering user utility is established for capacity allocation and user behavior-based electricity pricing. Second, the model is converted into a single-level mixed-integer linear programming model using the piecewise linear utility function, Karush–Kuhn–Tucker (KKT) conditions, and linearization methods. Finally, to verify the validity of the proposed model and the solution algorithm, a commercial solver is used to solve the optimization model and obtain the planning scheme. The results show that the proposed bi-level optimization model can provide a more economical and reasonable planning scheme than the single-level model, and can reduce the investment cost by 8.84%, operation and maintenance cost by 13.23%, and increase net revenue by 5.11%.

**Keywords:** PV-storage charging stations; green energy; planning process; bi-level optimization; user utility
