High Voltage Direct Current (HVDC) interconnections started to spread across land and underwater becoming longer and more powerful. The advance of this technology makes them the prime option for bulk power transmission in future. While on land the length can reach thousands of kilometres underwater they measure less than 600 km. The constraints but also the future developments must be addressed in order to assess the perspectives of this technology.
JRC is currently performing a study to identify and analyse the technical and geopolitical challenges for building an offshore electricity transmission interconnection between Europe and North America. The project "Offshore Transnational Grids - Technical and Geopolitical Implications" (acronym OTG) runs from 1 January 2015 until 31 December 2016.
The HVDC Submarine Power Cables in the World. State-of-the-Art Knowledge report is the first deliverable of the OTG project. It provides an extensive study on the availability of the technologies required for the realisation of a HVDC interconnection between the European and North American Alternating Current (AC) transmission grids.
The report revises the main submarine power cables in the world along with their characteristics. The main configurations and layouts are described. Information is provided regarding geological and path surveys, subsea bed topography, geological structure and lithology. Geodynamic processes, sea currents, waves as well as temperature and salinity are also discussed. Special attention is given to the installation of HVDC submarine cables. Techniques for laying a cable are discussed. Also issues such as protection measures and maintenance aspects are dealt with. The operation of HVDC submarine cable is treated as well. Reliability and accident risk issues are discussed in a dedicated paragraph as well as environmental aspects.