Maritime inventory routing means planning for transportation of bulk goods by ship between ports where the goods are produced and consumed, while avoiding stockouts and storage overflows in the ports. The combination of vessel routing and inventory management, and the coupling that arises between vessels that visit the same storage, make inventory routing a highly complex task.
Compared to road-based transportation, maritime operations have several characteristics that make integration of inventory management and routing relevant. The quantities transported are large, both in terms of vessel capacity and storage capacity at production and consumption facilities. In addition, travel times between facilities are considerable. This leads to a planning problem where routing decisions have a large impact on the inventory levels, and vice versa. Additional complications can arise from constraints such as draft limits, and onboard stowage and cleaning requirements between different products.
In close collaboration with industry, SINTEF has developed Invent - a generic industrial solver for maritime inventory routing problems. One of the world's largest energy companies, ENGIE, utilizes Invent to optimize shipping of Liquid Natural Gas (LNG).