Assessing the offshore wave energy potential for the Maltese islands

Abstract

Direct wave observations using a Datawell buoy deployed to the west of Gozo, and a numerical wave modeling exercise targeted to map the spatial and temporal signatures of the wave fields around the Maltese Islands over a span of five years (1st January 2007 to 31st December 2011) have been conducted within the BLUE OCEAN ENERGY® project. This has provided a detailed characterization of local wave climates and an estimation of the available wave energy potentials in the coastal and offshore areas of the Maltese Islands. This data is essential to assess the overall feasibility of constructing wave energy production farms based on WECs, to test the most adequate devices to harvest wave energy, as well as to identify the best candidate sites for an optimal and most economically practical extraction. The study reveals that the best sites in the Maltese waters would be those located at the western approaches to the islands, given that these are more exposed to the prevailing North-Westerly winds. At these sites, maximum significant wave heights can exceed 7 m in winter, even in close proximity to the coast, and with a seasonal mean of 1.92 m as determined from direct measurements. The mean wave power transport during the winter season is estimated at 15 kW m-1; the wave resource is more than halved in spring and even weaker in autumn; it is under 2 kW m-1 during summer. Stronger wave fields occur at a few kilometres to the South West of Filfla Island where the modelled mean wave power reaches values of 13 kW m-1 in the winter months, but at less accessible sites and greater distances from shore.