However, reinforcement costs at the distribution level were not considered in this analysis, due to the lack of systematic data on this issue. With the ambitious 2020 renewable targets set by the European Commission and the recent decision taken by the German government to phase out nuclear energy, the North Sea becomes a key source for Germany's energy supply and energy security. A big challenge for Germany will be to properly connect the renewable production from the northern part of the country with the big industrial demand centres located at the southern part of the country. A study published in 2010 (Weigt et al.,