考慮車輛到電網之電動公車充電排程問題

The Charging Scheduling Problem for Electric Buses Considering Vehicle-to-Grid

市區公車電動化是綠色交通發展的一大趨勢，然全面電動化帶來的能耗將會對電網造成巨大負擔。近年來，許多國家採用車輛到電網(Vehicle-to-Grid, V2G)技術，將車輛電池作為儲能裝置，於電網負載嚴重時將電能釋放回電網，藉此緩解運具電動化對電網的影響。本研究考量未來使用V2G技術下之電動公車充電排程問題，求解電動公車於公共充電站的最佳充電和供電時間表。考量執行班次時之耗電量不確定情形，本研究採隨機規劃模式，以離散機率分配描述耗電量隨機性，並利用GUROBI軟體求得最佳解。結果顯示模式能夠有效產生電動公車車隊的充電和供電排程表。另透過對重要參數進行敏感度分析，並通過模擬評估方法比較確定性模式和隨機模式績效，研究成果可做為業者規劃充電排程之參考。

Urban bus electrification is a major trend in the development of green transportation, but the increase in energy consumption is expected to cause a huge burden to the power grid. In recent years, a technology called Vehicle-to-Grid (V2G) is increasingly being adopted in many countries. Using the battery of electric vehicles as an energy storage device and releasing the additional electric energy back to the grid when the grid is under heavy load, it may be helpful in alleviating the impact of the full electrification on the grid. This study addresses the electric bus charging scheduling problem, with consideration of future V2G applications. The problem aims to determine the optimal schedule of charging and discharging for electric buses at public charging stations. Moreover, to deal with the uncertainty in energy consumptions, this study describes the uncertain energy consumption of electric buses using a discrete probability distribution and formulates the problem as a stochastic programming model. The proposed model can be efficiently solved by using GUROBI. The numerical results show that the proposed model is effective and efficient to generate the charging and discharging schedule for the fleet of electric buses. In addition, this study also conducts sensitivity analysis on important parameters in the model, and compares the performance of the deterministic model and the stochastic model through a simulation evaluation method. The analysis results provide valuable insights and can serve as a reference for operators in planning electric bus charging and discharging schedules.