Although offshore wind projects in the Baltic Sea have escaped some of the problems seen in the German North Sea, developers still face challenges with the potential for significant delay, says Udo Christiansen, project manager at the 288MW Baltic 2 plant for utility EnBW.
“Allow for (sufficient) time if you plan to build a wind park in
that region,” Christiansen told a conference on offshore wind energy in Hamburg.
Water depths of between 23- and 44-metres as well as a tricky
geology are particularly challenging, Christiansen said.
Next to sand and sedimentary till formed in the melting process of
the ice-age glaciers, foundations have to fight their way through extensive
layers of chalk below the Baltic's seabed.
Guidelines from Germany’s
maritime and hydrographic agency on how to deal with chalk deposits are very
complicated, Christiansen said.
EnBW is using both monopile and jacket foundations at Baltic 2,
but Christiansen admitted that“monopiles are terrible in that region".
To create a stable anchor, the
foundations penetrate up to 36-metres deep into the ground, the German utility reckons.
EnBW had to first run a test-pile programme to ensure that
foundations can resist wind, weather and waves for at least 25 years. That
programme lasted nine months and cost €12m, Christiansen said.
Judging the impact of ice covering parts of the Baltic
Sea during the winter adds to the headaches.
Christiansen said there are only four specialists in the world who
can carry out precise calculations on how ice affects offshore wind parks. EnBW has contracted one of them, a Finnish expert.
Laying energy cables also is more difficult than foreseen as they
have to circumvent riffs and rocks that cannot be crushed, partly for
environmental reasons, he said.
Despite the challenges, EnBW hopes to bring Baltic 2 into full
operation by the end of 2014 as planned, Christiansen said.
He added that on the upside, weather conditions in the Baltic are
better than in the North Sea, helping
installation. Also, the grid connection in the Baltic is less complicated as
parks tend to be closer to the coast, he said.
Transmission system operator (TSO) 50Hertz has told EnBW that a
grid connection for the park is guaranteed in time, Christiansen said.
EnBW recently secured a €500m ($668m) loan from the European
Investment Bank for Baltic 2. The wind farm will feature 80 Siemens SWT 3.6-120
turbines and be located 32km north of the island of Rügen.
operates the 48MW Baltic 1 wind farm and holds licenses for two offshore wind
projects in the German North Sea.