Optimising infrastructure and charging strategies for bidirectional electric delivery fleets under PV, grid, and cost constraints

The electrification of delivery fleets offers significant opportunities for decarbonising urban logistics, yet it also introduces complex challenges in balancing infrastructure investments, operational flexibility, and energy system integration. This paper presents a strategic optimisation model formulated as a Mixed-Integer Linear Program (MILP) to support long-term infrastructure planning for electric delivery depots. The model jointly optimises photovoltaic (PV) capacity, stationary battery storage, vehicle batteries, grid connection limits, and bidirectional charging strategies. A case study of a Swiss parcel logistics company serves as the empirical basis, with two depots of different scales analysed to assess how local conditions shape optimal solutions. Real-world data, including vehicle schedules, energy consumption, PV yield, and dynamic electricity tariffs, are used as inputs. Results show that site-specific modelling is essential, as no general conclusions can be drawn across locations. At smaller depots, PV and modest stationary storage provide most benefits, while bidirectional charging adds limited value due to daytime vehicle operation. At larger depots with higher demand, bidirectional charging of trucks and increased storage capacity become more advantageous. The findings highlight the need for tailored electrification strategies and provide actionable insights for logistics operators, energy providers, and policymakers.