Operating and Extreme weather conditions for testing Offshore Devices at Marine Renewable Energy Lab (MaRELab)

Abstract

Marine Renewable Energy Lab (MaRELab) is an onshore/offshore infrastructure for testing full and model scale prototypes aimed at harvesting energy from marine renewable sources.It is a real environment testing site located in the port of Naples, in proximity of the final part of San Vincenzo artificial breakwater. The laboratory covers an area of about 4 km², including 40 meters along the breakwater, and moving 200 meters in the seaside from this. Just few meters from the breakwater, it is possible to reach about 30 meters deep, allowing the correct scaling of the behavior of platforms in deep and intermediate waters. Due to its facilities, MaRELab enables to test different kind of devices. On the breakwater area for example is currently installed the OBREC device (Overtopping BReakwater for Energy Conversion), that exploits the overtopping phenomenon in order to produce energy. In the sea area, instead, floating wind turbines with scaling up till 1:7 approximatively can be installed. Furthermore, other floating devices, such as solar islands, innovative breakwater, can be tested, both individually or combined.The opportunity of investigating these technologies in a real environment allows to evaluate the effective dynamic, structural and energy performances, as well as the effective resistance of materials. Moreover, some physical phenomena are clarified due to higher scaling with respect to indoor laboratory tests. The optimal testing of the different technologies requires an extensive knowledge of the meteorological and marine conditions at the pilot site. For this purpose, in this work, wind and wave energy resources are assessed. In particular, wind and wave hourly data from re-analysis ERA5 dataset (ECMWF) are considered. Data cover the period 1979-2020 and are available for fixed geographical points. In order to characterize more in detail nearshore conditions, wave data have been propagated through the software MIKE21 SW.The energy resource assessment represents a practical guide in defining the optimal testing conditions. It provides information on the distribution of wind and wave energy resources at MaRELab during the year. Moreover, it is possible to investigate the correlation of the two resources [1]. The characterization of the site and the knowledge of the technology to be tested, suggest when the optimal meteorological and marine condition occurs. An Extreme Value Analysis has been carried out to define extreme wave conditions with several return period [2]. Operational and extreme condition, depending on the scaling of the devices, can thereby be realized.

REFERENCES

1.        Contestabile, P., Russo, S., Azzellino, A., Cascetta, F., Vicinanza, D. (2022).  "Combination of local sea winds/land breezes and nearshore wave energy resource: Case study at MaRELab (Naples, Italy)", Energy Conversion and Management, ISSN 0196-8904, 257, 115356, https://doi.org/10.1016/j.enconman.2022.115356    

2.       Dentale, F., Furcolo, P., Pugliese Carratelli, E., Reale, F., Contestabile, P., & Tomasicchio, G. R. (2018). Extreme Wave Analysis by Integrating Model and Wave Buoy Data. Water, 10(4), 373. ISSN: 2073-4441. https://doi.org/10.3390/w10040373