Evolutions and challenges towards a potential Pan-European HVAC/HVDC SuperGrid

SUMMARY The European power transmission grid is on the critical path to meet the European Union (EU)’s climate change and energy policy objectives for 2020. This trend is expected to continue also for the years after 2020, in view of ambitious decarbonisation targets by 2050. The main challenge will be the power system integration of very large amounts of variable renewable energy sources (RES), especially wind and also solar, while keeping overall system reliability at acceptable levels, in a liberalised background. To this scope, a more flexible, yet robust, transmission grid is needed. In presence of several issues more frequently constraining the realisation of new High Voltage Alternating Current (HVAC) overhead infrastructures, the need for evolution in the design and operation of transmission system towards a re-engineering process emerges in Europe. Among the different measures to support such shift, there may crucially be the use of High Voltage Direct Current (HVDC) technologies for advanced power transmission. The present paper, which partially results from the ongoing activities within the European research project REALISEGRID, investigates the role of HVDC towards the development of the future transmission system in Europe: particular attention is paid to current evolutions and challenges ahead of the potential realisation of a pan-European (mixed HVAC and HVDC) SuperGrid in a long term view, also in line with the recently issued European Commission’s Energy Infrastructure Package. After introducing key technical, economic and environmental characteristics of HVDC technologies, this paper reports some specific long-distance HVDC applications for bulk power transmission in extra-European systems towards potential SuperGrid implementations in Europe. The developments at the eastern and southern edges of the European system as well as across the North Seas, the Baltic Sea and the continental network are then specifically investigated in their evolution stages as potential building blocks of a long term pan-European SuperGrid.