Accelerated expansion of the 110 kV grid is also needed, says Hans-Josef Fell of the Greens Party. Between 2004 and 2006, transmission bottlenecks in the 110 kV grid kept some 74 GWh of potential wind generation off the system in the windy northern German state of Schleswig Holstein, adds Peter Ahmels from environmental group Deutsche Umwelthilfe (DUH). More wind will be wasted unless expansion of grid capacity at the 110 kV level is accelerated, he says.
New regulation taking effect this year, requiring that compensation be paid for wind power curtailed by grid operators, is likely to add economic pressure to the call for action, says German wind association Bundesverband Windenergie (BWE). That money could be better spent, it argues. If 1% of annual wind generation, amounting to 40 TWh, is curtailed, compensation paid to wind plant owners, at an average EUR 0.09/kWh, would amount to EUR 36 million-enough to cover the additional costs of putting 120 kilometres of cabling underground rather than in the air, it says.
Furthermore, giving underground cables the same status as overhead cables in planning approval procedures would resulting in swifter permitting with fewer appeals, adds DUH. Putting transmission wires underground is gaining acceptance across Europe, notes BWE, despite the added expense. It points out that Denmark is putting its 132 kV and 150 kV regional networks underground and French network operator RTE has pledged to lay at least 30% of new or replacement high voltage wires below the surface.