Co-Optimization of the Sizing and Dispatch of Microgrids Considering Vehicle-to-Grid and Arbitrage

Failure to model the optimal microgrid dispatch strategy simultaneously to the system design has the potential to impair the economic viability of the system as a result of less predictability of the future operating states of the system. That is, the business-as-usual rule-based, heuristic operational decisions, which use specifically devised, fixed energy management frameworks and lack any foresight of future system conditions, are prone to excessively oversizing the system (resulting in increased cost) or undersizing the system (leading to poor reliability), which respectively represent potentially over-conservative or inadequate microgrid planning decisions. In response, this paper introduces a novel operational planning optimization formulation that determines the year-long optimal multi-component schedules over a moving one-day horizon, where dispatchable and non-dispatchable distributed energy resources and vehicle-to-grid capacities are present in the system with the option to exchange energy with the wider utility grid. Nesting the proposed optimal dispatch strategy into a standard metaheuristic-based microgrid sizing model, such that the optimal design and dispatch problems are decomposed into separate sub-problems, produces systematically coordinated investment planning (long-term) and operational scheduling (short-term) decisions that adequately value the operational benefits of arbitrage strategies by algorithmically seeking out minimum operational costs. Importantly, the simulation results from populating the proposed model for a hypothetical test-case system indicate a significant ~24% reduction in energy costs compared to the business-as-usual scenario.