A first cable connecting the Borssele Alpha offshore substation in the Dutch North Sea to the transformer station at Borssele has made landfall, transmission system operator Tennet said Tuesday.
The cabling project, for the 752 MW Borselle 1 and 2 wind farm, is expected to be completed later this year.
Installation of 94 offshore turbines (8 MW Siemens Gamesa machines) will then start next year with the project on track for a 2020 start, developer Orsted said recently.
Tennet is responsible for connecting Dutch offshore wind farms to the grid. Between now and 2030 10 GW of capacity will be connected, including the world's first 2 GW HVDC subsea cables connecting the IJmuiden project planned to come online from 2027.
Tennet's standardized concept for 750 MW AC cables with 220 kV voltage is being used for five projects under the Netherlands' 2013 accord (of which Borselle is the first) as well as the first three projects under the country's 2030 roadmap.
Offshore wind costs have fallen sharply in recent years due to larger turbines, learning effects and other economies of scale.
Nevertheless a recent study by Germany's DIW commissioned by Orsted argued that German offshore wind connection processes were sub-optimal compared to those in the UK.
Instead of isolating the grid element and putting national TSOs in charge of delivery, the study argued for a competitive, integrated wind farm/connection model as used under the CfD/OFTO regimes in the UK. This could save German projects around Eur10/MWh on average, DIW said.
In a response sent to S&P Global Platts Tuesday, Tennet, which is also responsible for German North Sea offshore grid links, defended the German model and its focus on DC technology.
German offshore wind farms were generally further offshore than those in the UK and no other operator had Tennet's experience in delivering such projects, it said.
Tennet's oversight had allowed it to reduce the original 13 North Sea grid corridors as envisaged by developers to just four, it said.
"In addition, the Orsted option would threaten to limit the diversity of actors in offshore wind as there are very, very few companies that have the technical and financial resources to design and build offshore connections," a Tennet spokesman said.
With a total investment volume of Eur4 billion-5 billion for wind farm and grid connection, medium-sized companies would be priced out of tenders, it said.
