Opportunities and barriers of high-voltage direct current grids: a state of the art analysis

Limiting the consequences of the climate change means that global CO2 emissions are to be reduced very rapidly. Taking into account that the expected economic growth of developing countries will inevitably be accompanied by a further growth in emissions in these countries, there is a strong necessity that the energy systems in the industrialized world be transformed into emission-free ones. This level of reduction requires, for example, that the European Union achieves a 'nearly zero-carbon power supply', involving replacing of fossil fuels in most or all buildings and much of the transport sector by nearly zero-carbon electricity. It is also clear that the current political framework is, especially in Europe, propitiating the large-scale implementation of renewable energy sources. In order to make this large implementation economically feasible, it is essential that the potential of these sources is maximized, placing them at sites providing the highest possible output. These sites are often located far away from consumption centers, making compulsory the transmission of large amounts of energy from generation to demand. In the global scenario, the necessary capacity of the power infrastructure for doing such exceeds by far the existing infrastructure and therefore new transmission capacity is necessary. Taking into account that large amounts of Renewable Energy Sources (RES) are to be integrated in the current power system and that most of the generation will take place at remote locations requiring new transmission assets, this article answers the question of whether a supergrid is necessary to enable this transformation. (C) 2012 John Wiley & Sons, Ltd.