TenneT faces formal investigation over cable delays

Dong prompts regulator to query DolWin 1 & 3 progress

Complaints by Dong Energy have prompted German energy regulator, Bundesnetzagentur, to commence formal investigations into delays in grid connection projects for two wind farms, Borkum Riffgrund 1 and 2.

Two formal complaints were submitted by German development companies owned by Dong. They focus on the planned DolWin1 cable, which will link Borkum Riffgrund 1 to shore, and the yet-to-be-confirmed DolWin3 cable, expected to link Borkum Riffgrund 2.

Both projects are the responsibility of transmission system operator, TenneT, which has struggled to build new offshore cables fast enough to keep pace with offshore wind construction in the German North Sea. Last year, TenneT's difficulties were a key factor in the passage of new legislation designed to encourage extra investment in its programme of offshore grid expansion. Since the new legislation was passed Mitsubishi has bought stakes in four TenneT offshore cable projects.

Under paragraph 31 of Germany's energy industry act, a complainant must present firm reasons why it has "serious doubts about the legality of the network operator's behaviour." The regulator has two months to evaluate the complaint, with the possibility of an extension.

This is not the first time that Dong has expressed a lack of confidence in TenneT's ability to grid connect Borkum Riffgrund 2 on schedule. Last autumn, it announced it was putting Borkum Riffgrund 2 officially on hold – and focusing on UK projects instead – because of the grid connection delays.

Windreich subsidiary, British Wind Energy, launched a similar procedure against TenneT in August 2012 over delays with the BorWin4 cable by which its Deutsche Bucht project was slated to be connected to shore. The complaint was withdrawn a few months later, after Windreich and TenneT agreed that Deutsche Bucht could be temporarily connected to the Borwin 2 cable - already under construction -  until BorWin 4 is completed.