The German federal network agency and grid authority, Bundesnetzagentur, reported at the end of May 2011 on the implications of plans to close down nuclear generation. "The historically singular simultaneous shutdown of power plants amounting to 5,000 MW capacity and the long-term lack of some 8,500 MW capacity bring the transmission grids to the edge of their resilience."
Consequently there are many hours in which secure network operation is impossible, meaning that it is vulnerable to a single failure. "As a consequence, the original objective of competition-driven market results is replaced by a more or less centrally controlled planning approach.
This is dubious in terms of energy economics, economically inefficient and ecologically harmful, but must be accepted for a transitional period and is unavoidable at the moment." Reserve capacity is fully utilised, no buffer is left, and "For this reason the risk of non-controllable network disturbances is increasing distinctly." The summer "risk will increase markedly during the winter semester due to higher load on the network linked to higher domestic and foreign power demand and significantly lower PV generation."
While PV and wind together sometimes contribute up to 28 GW, "leading to a manageable network situation" during favourable spring weather conditions, it is evident "that this capacity is not available in a reliable manner, but regularly disappears completely.
" Also, "The changed network load pattern due to the shutdown of the 7+1 nuclear power plants has already led to postponements of scheduled service and maintenance works in the transmission grid, because many such works can only be undertaken when there is little or no load."
This has obvious implications for reliability. "Maintenance work at transformer station Großkrotzenburg, a major north-south network node close to Frankfurt, for instance, had to be postponed because the relevant circuits are indispensable." Bundesnetzagentur warns of very uncertain supply situations likely over winter, especially in southern Germany, along with increased costs. In case of a permanent shutdown of the eight nuclear reactors affected by the moratorium, Germany can no longer support security of supply in the European interconnected grid to the extent it has done so far.
Hence the German situation has implications much more widely in Europe, as the country becomes a net importer of power rather than major exporter, and grid stability is the other major concern along with generation and transmission capacity.
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