Underwater cable to the user 2.01.2012
COMPARISON WITH OFFSHORE WIND The consenting process for the installation of the cable is similar to the one usually applied to offshore wind. The main difference is that usually the installations based on R115 or H24 machines top up at a few megawatts of power, and therefore the cable is much smaller than the one used in offshore wind parks. The installation process does not need a large, purpose built vessel, but can be performed by a standard towboat on whose deck the cable laying mechanism has been temporarily welded. The installation process for R4M machines is very similar to that of offshore wind turbines.
AUTHORIZATION PROCESS The authorization process for underwater cable laying and for its landfall is usually well known and documented in any jurisdiction, and the fact that on the offshore end of the cable there is a Wave Energy Park instead of, say, an offshore platform, should not introduce any uncertainty in the process. Our partners can assist you in the preparation of the project.
ELBA ISLAND In the case of Elba Island, in the north Tyrrhenian sea, the authorities gave the go ahead to the cable laying on the basis of the considerations above, even if the island is one of the most protected and pristine areas in the whole Mediterranean sea.
CABLE LANDFALL AND TRENCHING The cable will make landfall preferably in a (small) harbor, to minimize the environmental impact at the site. However, considering the very reduced diameter of the cable itself usually it is easy to obtain the permits to lay it even on valuable sea floor. In this case it is preferable not to trench the cable, and either to leave it on the surface of the sea floor possibly inserting mattresses every now and then to stabilize it (if there is no danger of anchoring or dragnet fishing) or to include it in a steel pipe otherwise. If trenching cannot be avoided in certain parts of the cable path, it will need to be carefully planned. In this case a study of the sea floor might be needed, and we can direct to our partners for this.
POSSIBLE INTERFERENCE WITH DRAGNET FISHING The presence of the cable may limit the possibility to perform some forms of fishing, specifically dragnet fishing if the cable has not been buried. This might be a problem in certain locations, and a mitigation of the problem can come either from the trenching of the cable, or from the laying of the cable inside or on the boundary of protected areas where dragnet fishing is not allowed, or finally by actively including the local fishing community in the activities of the Wave Energy Park as a form of compensation for the limitation on their activity. The specific solution will depend on the site and there is no general one.