A strategy for optimizing the operation of photovoltaic (PV) and other power generation systems developed by Mitsubishi Electric Corporation also optimizes the charging/discharging of electric vehicles (EVs) parked on company campuses.

A multi-directional power conditioning system (PCS) calculates minimized power costs in order to reduce or shift the use of grid power during peak hours. Charging/discharging of EVs parked at a user's company is coordinated with the use of PV and other power-generation systems as the system forecasts power demand and PV power generation.

The system regularly monitors the status of EVs connected to or disconnected from the PCS, minimizes power costs by using connected EVs as storage batteries and refines the charge/discharge schedule every few minutes, thereby minimizing power-cost increases due to any unexpected use of EVs.

The calculations consider contracted power from the grid, electricity unit prices, power demand and expected use of EVs in the fleet under the constraints of the received-power capacity, supply-demand balance, and the maximum and minimum charge/discharge levels of EVs and on-site storage batteries.

Simulations for a 10 EV scenario indicate vehicle power costs to be five percent less than in the case of using no energy-management system.

Energy-management system for power generation and power storage. Source: Mitsubishi Electric CorporationEnergy-management system for power generation and power storage. Source: Mitsubishi Electric Corporation

To contact the author of this article, email shimmelstein@globalspec.com