Energy efficiency of maritime operations is an increasing focus for maritime companies as the energy prices rise and the alternative fuel engines are still being researched.  Great energy efficiency can be achieved through improved planning of the highly complex maritime operations. Different models and algorithms solving problems within maritime are presented involving speed optimization, berth scheduling, network design, stowage and cargo allocation. This work assists shipping companies in reducing fuel consumption, lower emissions, and improve operational efficiency while maintaining service reliability and economic performance. Existing work and work in progress will be presented with the hope for a fruitful discussion with the audience.