The power surges occurred because German and especially Dutch power suppliers attempted to make up the sudden shortfall caused by the German shut down by importing hydro power from Switzerland and France via Belgium's relatively small high voltage grid. The combined installed capacity of the wind farms involved was 13 GW, while the total installed capacity of Belgian power stations is 14 GW, says Belmans. He cautions that the problem will be exacerbated by the construction of large offshore wind farms if they are not supplemented by adequate high voltage connections to neighbouring countries.
The Belgian wind sector, however, has moved swiftly to counter Belmans' claims. With just 400 MW of offshore wind in the pipeline to feed into the Belgian grid, there is absolutely no threat from offshore wind, says Filip Martens of C-Power, the developer of a 300 MW wind farm on Thornton Bank some 30 kilometres off the Belgian coast. Furthermore, under existing legislation, wind farm operators are responsible for ensuring continuous supply levels by arranging adequate back-up, points out Martens.
The threat posed by German wind farms simply demonstrates the inadequacy of the Belgian national grid when confronted by the demands of the European liberalised market, says Martens. "It's not specifically a problem with wind. It's clear to everybody that transmission networks throughout Europe -- and particularly in Belgium -- need to be upgraded to cope with the new sort of demand arising from cross border trading.
"We need to find creative solutions to this problem at a European level. One solution might be to lay an undersea cable that could connect the various member states -- and incidentally provide a feed for offshore wind as it passes. We should certainly be investing in researching this sort of issue rather than throwing more money at studies of nuclear energy."
Belmans says that Elia is currently working on equipment that will make it possible to limit power volumes -- transferring the problem to neighbouring countries. Peter Puyk of the Dutch national grid operator Tennet says the north German wind farms only introduce an element of uncertainty into the management of flow on the Dutch transmission network but pose no threat to operations.