Pelagian were contracted by a major international engineering consultancy to provide expertise on permits for a proposed HVDC power cable between Italy and Tunisia in the Mediterranean Sea.
The study researched the maritime jurisdictions of each of the countries crossed by the proposed cable and the permitting and regulatory requirements for the survey and installation of a subsea power cable.
The work scope also researched the environmental requirements at the landing points and coastal shelf areas and also stakeholder requirements for the crossing of a significant number of active telecom cables and oil/gas lease blocks.
Case Study: Cable Burial Operations on Arklow Bank Offshore Wind Farm
In 2004 one of Pelagian’s first projects in offshore wind was the successful trenching of wind farm cables using a Gator trencher on Arklow Bank in the Irish Sea.
Arklow Bank wind farm is located on a shallow sandbank 14km off the East coast of Ireland and is the country’s first offshore wind farm consisting of 7 turbines and generating 25MW of power.
Pelagian provided the offshore expertise and project management to operate the Gator trencher. Gator is a tracked, self propelled shallow water cable trenching system, fitted with a chain cutter, enabling cable burial up to 2m in the shallow sand deposits and which provided a cost effective and comprehensive subsea cable trenching solution.
Case Study: Main One Permitting Consultancy Services
Pelagian were contracted to provide permitting and regulatory services to the Main One Cable System project, working on behalf of the cable installer and system owners.
The work scope consisted of detailed in-country data gathering at a diplomatic level in all but one of the North and West African countries from Morocco to Nigeria and development of the data into a sophisticated permit management system which was used to track the requirements, progress and costs associated with each country.
The permit work encompassed detailed knowledge of government and regulatory requirements for cable landing points, work in Territorial seas, traverse of EEZ waters, crossing of oil/gas concessions and negotiation of agreements for both survey and cable installation. The work was successfully completed without delay or penalty, considered a first in the history of a West African cable project.
Case Study: Main One Geophysical Survey
Pelagian in partnership with a major international survey company, successfully bid for the Main One Cable Route Survey in 2008. This was a significant landmark in Pelagian’s history and the company’s largest single contract award at that time.
The scope of work comprised geophysical surveys for the Main One cable system from Portugal to Nigeria from landing point to deepwater. Pelagian provided expertise in cable route engineering and landing point selection, operational permitting for the survey vessels and burial assessment knowledge to the CPT sampling campaign.
The project was successfully surveyed in 2009 without any delays caused by permitting or regulatory constraints, considered a first in West African cable survey experience. Pelagian also provided permitting expertise for the successful installation of the cable in 2010.
Case Study: Annual Depth of Burial Survey
Pelagian has been providing annual depth of burial surveys on a subsea telecom cable in Europe for the last 10 years. This cable is located in an environmentally sensitive shallow water area, where numerous cables from both telecoms and offshore renewables / power make landfall in Northern Europe.
The seabed in the area is prone to sediment mobility, potentially exposing the buried cable to external risks such as fishing and anchoring. The area has also recently seen a number of new projects with increased construction shipping activity, serving the offshore wind farms.
The survey is undertaken using high resolution multibeam bathymetry, sidescan sonar and subsea cable tracking equipment mounted on a sled. This is used to determine the depth of cover of sediment and enable direct comparisons with the previous years’ survey, to monitor the burial status of the cable.
