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The work started work in early May 2003 and by sailing four complete
turbines per trip, the last turbine was installed in July 2003.
A2SEA had learned quite a lot from the first project at Horns rev, and
the most significant lesson learnt was to put great emphasis on the
seabed conditions for jacking the vessel, as some base plates were
lost at one occasion.
The most significant upgrade was a sonar well fitted on the vessel in
order for the jacking crew to see debris and other obstacles on the
seabed.
After completing the Nysted wind farm, the vessel Ocean Ady went
on to Arklow Bank to install a met mast, and this was the first job
installing monopiles. The project was carried out during October,
and while Ocean Hanne was on Horns Rev for planned maintenance,
Ocean Ady stayed on Arklow for commissioning of the seven GE
turbines there.
In December A2SEA was once again awarded a contract of installing
offshore turbines, this time the Scroby Sands project, where 30 Vestas
2 MW turbines were to be installed from March to May 2004. And
this time the challenge was to cope with 5 knots of current in very
shallow water. In fact some of the turbines would be dried out during
Spring tides.
During January a new set of base plates were designed, and fitted on
to the legs of Ocean Ady and the vessel was mobilized during late
February and early March. The reason for the new base plates was
that A2SEA believed that in order to keep the vessel stable during
jacking in the high currents, the company needed to penetrate the
seabed to the maximum scour that would occur. This is not normal
10 Offshore Center Denmark
Newsletter ON/OFF 3 - August 2004
operation as you want to stay on top of the seabed for easy access and
egress to each position, but the risk of underscouring a base plate was
so big that it was decided—rightly—to install new tailor made plates.
The installation of the turbines was split between A2SEA and Seacore
—a British offshore contractor who in cooperation with A2SEA
installed 6 of the 30 turbines on the shallowest locations.
The contract was completed late May and again A2SEA has fulfilled
a contract prior to the agreed time schedule to the client’s satisfaction.
At the moment the company is busy at Horns Rev, as well as in the Baltic
Sea, where a number of gearboxes on a wind farm will be replaced.
In fact, A2SEA believes that the service and maintenance will be a
major field in this industry, and A2SEA has already carried out more
than 90% of the service contracts in the market so far.
The company has grown from only one to 26 people employed today,
and the offices located in Fredericia are perfect, being close to all
major turbine manufacturers as well as the utility companies that are
among the clients. Also for docking the vessel the location is good
and A2SEA has now done further modifications in the local shipyard.
All in all it has been an exiting four years since the company was
founded and A2SEA takes great pride in the fact that it has installed
the large majority of the offshore turbines in Europe and has serviced
most of them always effective, always safe and always on time and to
the agreed conditions. A2SEA thinks that this is their best recommendation
for their future customers.■