The
transmission system operator, TenneT has brought the fifth grid connection
system DolWin1
into operation this year. This means that the offshore grid connections
in the North Sea now achieve a transmission capacity of around 4,300 MW.
TenneT has thus now fulfilled two thirds of the federal government's expansion
targets of 6,500 MW by 2020.
ABB has successfully commissioned and
handed over the DolWin1 offshore wind grid connection to the Dutch-German
transmission system operator TenneT.
The DolWin1 grid connection is part of
Germany’s ambitious energy transition roadmap, called “Energiewende”,
which foresees the generation of more than 6.5 gigawatts (GW) from offshore
wind by 2020 and 15 GW by 2030.
"We are proud to have completed another of our technologically demanding
offshore pro-jects and to have taken another step closer to the federal
government's expansion target," said Wilfried Breuer, member of
the TenneT management team.
DolWin1
is already the eighth offshore grid connection brought into operation by
TenneT. Four additional grid connection systems for transmitting wind energy
from sea to land are under construction.
DolWin1
is a high voltage direct current (HVDC) transmission facility with a capacity
of 800 MW. The power line runs 75 km as a subsea cable from the DolWin
alpha converter station to the landfall point in Hilgenriedersiel and from
there 90 km as an underground cable to the converter station in Dörpen-West
(Heede), in Lower Saxony.
The wind power produced offshore is transmitted as three-phase electric
power to the TenneT DolWin
alpha converter platform, converted
to direct current and transmitted to the Dörpen-West converter station
via a direct current cable. There, the DC power is con-verted back to three-phase
electric power and fed into the extra high-voltage grid.
“We are proud to hand over the DolWin1 offshore wind grid connection to
TenneT and to make a significant contribution to Germany’s target of increasing
its share of renewables in the energy mix,” said Claudio Facchin,
President, ABB Power Systems division. “We pioneered HVDC technology
and have remained at the forefront of its innovation. We are pleased to
see it being leveraged to bring clean energy to millions of people reliably
and efficiently.”
The substructure of the DolWin
alpha offshore platform, known
as the jacket, was installed in the south-western North Sea in 2012. In
2013, the part protruding above water, known as the topside, was installed.
The platform, the size of which corresponds approximately to a football
field on five floors, was placed onto the substructure using the world's
largest floating crane. This was followed by works to complete the electric
facilities and auxiliary systems, both on the offshore platform and in
the onshore converter station in Dörpen-West.
Heerema Fabrication Group built DolWin
alpha in their yard in Zwijndrecht
(Netherlands) on behalf of ABB, TenneT's general contractor for this project.
ABB is responsible for platform construction and installation of all electric
facilities, where ABB utilises HVDC light converters as fundamental technology.