Dimitrios V. Lyridis

The paper introduces a framework of operation of maritime-related enterprises like port authorities and ship-owning or operating companies along with electric energy providers in the electric energy market as a consequence of the global decarbonization effort and, in particular, due to the implementation of ship electrification at berth. Within this context, the main rules of this energy market framework will consist of a proper combination of power purchase agreements along with contracts for difference in an attempt to obtain transactions that are mutually beneficial at least on a mid-term basis. The methodology, which is fully compatible with the electric energy market rules of the European Union, is enriched by a variety of alternative scenarios on the selling prices of electricity, showing that even when monthly or annual periods are used for reference, it is highly possible that all parties engaged have benefits.

In this study, we present a hybrid approach of Ant Colony Optimization algorithm (ACO) with fuzzy logic and clustering methods to solve multiobjective path planning problems in the case of swarm Unmanned Surface Vehicles (USVs). This study aims to further explore the performance of the ACO algorithm by integrating fuzzy logic in order to cope with the multiple contradicting objectives and generate quality solutions by in-parallel identifying the mission areas of each USV to reach the desired targets. The design of the operational areas for each USV in the swarm is performed by a comparative evaluation of three popular clustering algorithms: Mini Batch K-Means, Ward Clustering and Birch. Following the identification of the operational areas, the design of each USV path to perform the operation is performed based on the minimization of traveled distance and energy consumption, as well as the maximization of path smoothness. To solve this multiobjective path planning problem, a comparative evaluation is conducted among ACO and fuzzy inference systems, Mamdani (ACO-Mamdani) and Takagi–Sugeno–Kang (ACO-TSK). The results show that depending on the needs of the application, each methodology can contribute, respectively. ACO-Mamdani generates better paths, but ACO-TSK presents higher computation efficiency.