Paulo Rosa-Santos

CECO wave energy converter: Experimental proof of concept

This paper presents the experimental proof of concept of CECO, an innovative wave energy converter designed to convert simultaneously the kinetic and the potential energy of ocean waves into electrical energy, based on the oblique motion of two floating modules. First, the main characteristics of CECO and its work principle are briefly presented. Then, the behavior of the device is analyzed for different wave conditions and modes of operation (power take-off damping levels and device inclinations), based on results obtained with a physical model built on a geometric scale of 1/20. CECO performance strongly depends on the incident wave characteristics, the device inclination angle, and the damping introduced by the power-take-off. Relative capture widths of up to 14% were reached in this initial study, confirming that CECO is a valid technology to extract energy from waves. The application of wavelets showed that CECO response occurs mainly in the frequency of incident waves during the entire test duration.

Preface to Special Topic: Marine Renewable Energy

Marine renewable energy (MRE) is generates from waves, currents, tides, and thermal resources in the ocean. MRE has been identified as a potential commercial-scale source of renewable energy. This special topic presents a compilation of works selected from the 3rd IAHR Europe Congress, held in Porto, Portugal, in 2014. It covers different subjects relevant to MRE, including resource assessment, marine energy sector policies, energy source comparisons based on levelized cost, proof-of-concept and new-technology development for wave and tidal energy exploitation, and assessment of possible inference between wave energy converters (WEC).

Real-Time Tracking System for a Moored Oil Tanker: A Kalman Filter Approach

This paper presents a tracking system developed to study the behavior of an oil tanker moored at the Berth “A” of the Leixoes Oil Terminal, Porto, Portugal. A brief description of the local environmental conditions and the existing operational conditions at that oil terminal are presented. Due to extreme outdoor working conditions a Kalman filter was implemented to ensure the robustness and reliability of the obtained measurements. Tests were performed in laboratory on a physical model of a moored oil tanker at a scale 1/100. The results were compared with a commercial motion capture system installed in laboratory. The presented measurement system was developed as part of the DOLPHIN project that aims to study the behavior of moored ships in harbors.

Experimental study of solutions to reduce downtime problems in ocean facing ports: the Port of Leixões, Portugal, case study

Downtime at ocean facing ports is often related to excessive moored ship motions caused by wave action. This paper discusses the influence of local conditions on the operational problems at Berth “A” of Leixoes Oil Terminal, Porto, Portugal, and analyses the efficacy and suitability of selected interventions, either on the north breakwater or on the mooring system, to reduce the amplitude of moored ship motions. Mooring practices are also analysed. It was concluded that friction forces at the interface between the ship and the fenders have a significant effect on the moored ship response and effectively reduce ship oscillation amplitudes (especially the surge); while a slight modification of the mooring arrangement has a negligible influence on the ship behaviour. In addition, modifications to the harbour breakwater configuration taking into account local conditions improved Berth “A” operational conditions.