A strategy for building 2,150km more of subsea cables in the German North and Baltic Seas by 2023 has been outlined in Germany’s first draft offshore network development plan (O-NEP 2013). A total cost of €22bn is estimated, including the €12bn already spent on existing offshore grid infrastructure.
The O-NEP is a requirement of Germany’s newly-revised energy industry act and will be updated each year. Its introduction marks a dramatic change in the country’s approach to offshore network planning.
Under the old regulations, transmission system operators (TSOs) were legally obliged to complete a cable connection to shore by the time an offshore wind farm was ready to generate power. From this year, Germany’s offshore network will be expanded according to the O-NEP, and wind farms connected accordingly. The aim is to prevent “stranded investments” where offshore cables are built, but then not used.
In its current draft form, the O-NEP envisages installation of an additional 1,125km of high voltage direct current (HVDC) cables and 595km of alternating current (HVAC) in the German North Sea. In the Baltic, the plan is for about 595km of HVDC and 430km of HVAC.
These needs are based on a lead scenario - one of three - which assumes total offshore wind capacity of 14.1GW by 2023, of which 12.8GW is slated for the North Sea and 1.3GW for the Baltic Sea.
Germany’s so-called ‘start-network’ of existing offshore cables comprises 2,215km, split between:
- the AC system for the Alpha Ventus wind farm
- the BorWin1 DC system in theNorth Sea
- the AC system for Baltic 1
- the 11 network connections totalling just under 8GW already pledged to specific offshore projects.
O-NEP 2013 prioritises those network expansion options that can be installed most efficiently, then allocating capacity to one or several offshore wind projects. Frustratingly for developers, this second ‘allocation’ phase is to be carried out by the federal energy regulator at an unspecified date. But O-NEP lists the criteria that will be used to decide on the timing of grid connection projects:
1) distance from shore
2) location of the wind farm within areas prioritised for wind development
3) generation capacity of the offshore wind cluster
4) planned commissioning of the connection to the onshore network
5) development progress of project.
Released on 3 March, O-NEP 2013 is being created alongside an onshore network development plan (NEP 2013), covering the same period to 2023. The plans have been written byGermany’s four TSOs and are subject to two rounds of consultation.