Optimal Charging Strategy to Minimize Electricity Cost and Prolong Battery Life of Electric Bus Fleet

Abstract

Smart charging is becoming an important and indispensable asset for electric bus fleet to become economically competitive. This paper proposes an innovative approach for setting overnight charging schedules of electric bus fleet. This approach uses nonlinear programming in order to minimize both the electricity cost and the battery aging. The optimization is constrained by the operating buses conditions, the electric vehicle supply equipment, and the power grid. A comparison between the nonlinear programming results and non-dominated sorted genetic algorithm (NSGA-II) will show the difference and complementarities of both approaches and proposes a number of trade-off optimal solutions.

Reaping the Benefits of Smart Electric Vehicle Charging and Vehicle-to-Grid Technologies: Regulatory, Policy and Technical Aspects

“…The results were compared with non-dominated sorted genetic algorithm (NSGA-II) results. The simulation study has shown that, with multi objective pareto approach, both the objectives can be satisfied and can achieve 20% reduction in annual electricity cost and 48% reduction in battery aging cost [9].…”

“…3 Non-dominated sorted genetic algorithm (NSGA) [9] Operating constraints (number of buses, initial SoC and battery temperature, the targeted SoC, arrival and departure time, maintenance period), charging station constraints (number of charging points, maximum charging power), and power grid constraints (time-of-use, power peak demand) are considered in the algorithm.…”

“…Moreover, uncoordinated EV charging will also increase the operation cost. Since it will increase the peak demand and require expensive faststart generation units to cater for that additional demand, such as gas-turbine generators [9]. Similar consequences could be anticipated from the uncoordinated vehicle-to-grid (V2G) schemes.…”

“…Such a situation could be considered as an uncoordinated charging condition. A random or uncoordinated EV charging could adversely affect the distribution grid, such as an increase of real power losses, violation of voltage limits, and overloading of distribution network assets, such as distribution transformers and cables/lines [9]. Moreover, uncoordinated EV charging will also increase the operation cost.…”

A Scalable Approach to Minimize Charging Costs for Electric Bus Fleets

“…Battery electric buses (BEBs) are replacing diesel and natural gas buses in public transportation because they offer many benefits [1], including reduced maintenance [2], zero emissions [3], and access to renewable energy [4]. The challenge of prolonged charging times has been addressed in prior research with distributed charging networks [5], bus availability, environmental impact [6], route scheduling [7], battery health [8], the cost of electricity [9], and the cost of charging infrastructure [10].…”