0278-0046 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TIE.2018.2850030, IEEE Transactions on Industrial Electronics IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS Dynamic Economic/Emission Dispatch Including PEVs for Peak Shaving and Valley Filling Huijun Liang, Yungang Liu, Fengzhong Li, and Yanjun Shen Abstract —In the foreseeable future, plug-in electric ve- hicles (PEVs) will dominate the car market. Once the ran- dom charging behaviors of PEVs continue, a higher peak- valley difference would occur. In this paper, a new prob- lem on studying the dynamic economic/emission dispatch (DEED) including PEVs for peak shaving and valley filling is proposed, and furthermore, the effect caused by different vehicle-to-grid (V2G) and grid-to-vehicle (G2V) loads on DEED is analyzed. The optimization model of the problem is constructed including several practical constraints, such as power flow constraints and ramp rate limits. The battery degradation cost is also included, which reshapes the ob- jective function of DEED. Based on the model, a strategy for DEED including PEVs for peak shaving and valley filling is given, and a multiobjective optimization algorithm is adopted to solve the proposed problem. To demonstrate the feasibility and effectiveness of the proposed strategy, three DEED cases are considered under different V2G power. The analysis of the effect on fuel cost and emission caused by different V2G power shows that the proposed strategy can effectively reduce emission and cut down the investment in peak load plants. Index Terms—Dynamic economic/emission dispatch, PEVs, peak shaving and valley filling, multiobjective opti- mization. I. INTRODUCTION E CONOMIC dispatch (ED) is an important task in power systems, whose objective is to find the optimal schedul- ing for generators to minimize the total fuel cost under certain constraints [1]–[4]. With the increasing concern on environment, emission should be also included. This gives rise to the study of economic emission dispatch (EED) which is actually a multiobjective optimization problem [5], [6]. Since the EED is only suitable to a certain fixed time interval, the DEED is proposed, which aims at minimizing operation cost and emission simultaneously over a 24-hour time span [7], [8]. Manuscript received March 5, 2018; revised May 23, 2018; accepted June 8, 2018. This work was supported by the National Natural Sci- ence Foundation of China under Grants 61325016, 61703237 and 61374028, the Natural Science Foundation of Shandong Province under Grant ZR2017BF034, and the China Post-Doctoral Science Foundation Funded Project under Grant 2017M610424. (Corresponding author: Yungang Liu.) H. J. Liang, Y. G. Liu and F. Z. Li are with the School of Control Science and Engineering, Shandong University, Jinan 250061, China (e-mail: eric liang@mail.sdu.edu.cn; lygfr@sdu.edu.cn; lifz@mail.sdu.edu.cn). Y. J. Shen is with the College of Electrical Engineering & New Energy, China Three Gorges University, Yichang 443002, China (e-mail: shenyj@ctgu.edu.cn). As an indispensable part in future power systems, PEVs have gained sufficient concern due to the challenge of environ- mental problem and the energy shortage crisis [9], [10]. Some policies and plans about PEVs have been formulated by the main countries in the world. For example, PEVs will contribute to 60% new car sales in the UK by 2030 [11]. But with the in- creasing number of PEVs, the peak-valley load difference will further increase, which would result in extra load demand due to the random charging behavior of PEVs [12], [13]. So it is urgent to study the scheduling of PEVs while formulating the optimal dispatch scheme for power systems. Some previous works have been proven to be effective to tackle this problem. In [9], the framework, challenges, benefits and optimization algorithms of V2G technology were reviewed. The authors conclude that V2G is able to provide peak load shaving and load leveling services to power grid. In [14]–[18], different strategies were proposed to realize valley filling with G2V technology, but none involves peak shaving problem. In [19], a strategy for peak shaving and valley filling by PEVs was proposed, but the authors put the emphasis on minimizing the load difference between target load curve and available V2G plan curve. In [20], [21], two V2G dispatch strategies were adopted to achieve peak shaving, but all the studies do not consider the effect on economic and emission dispatch while using V2G. Currently, there are very limited works on the study of DEED problem incorporating PEVs for peak shaving and valley filling, especially on the study of the effect on DEED caused by different V2G/G2V loads when PEVs are used for peak shaving and valley filling. In [22], economic and emission objectives were included in the scheduling of PEVs by maxi- mizing the utilization of PEVs and renewable energy. In [23], a new scheduling method was proposed for DEED with PEVs, and the effectiveness was demonstrated with four different charging profiles of PEVs. In [24], DEED including PEVs was also studied, and an optimal dispatch result was given without considering how to control the charging/discharging behaviors of PEVs. In [25], an optimal charging schedule was proposed to minimize carbon emission considering both standard and V2G use of PEVs. The authors also conclude that it is beneficial to reduce carbon dioxide emissions when V2G is used during peak periods. In [26], the bidirectional dispatch coordination of PEVs was considered, and a DO model was proposed to minimize the total operation cost of thermal generators. But all the above works do not include