This report is the first deliverable of the OTG ("Offshore Transnational Grid") Work Package (2015-2016), which is intended to identify and analyse the engineering and geopolitical challenges for realising a transcontinental energy interconnection between Europe and North America. The paper first of all addresses the principles of a High Voltage Direct Current (HVDC) power transmission system. Special attention is given to submarine cable interconnections. The spatial context of these cables is discussed. The used technologies and materials are addressed as well as the methods used to install and operate the cables. Additional aspects, such as safety and environmental issues, are also discussed. Further the report gives an overview of operational and planned HVDC submarine power cable systems. An extensive inventory list of these cables is annexed. Finally a set of conclusions are put forward, primarily pointing at further actions of the Work Package.JRC.F.3-Energy Security, Systems and Marke
