Read News Magazine (pdf) - Offshore Center Danmark

More documents

Recommendations

Info

Experiences at Horns Rev Offshore Wind Farm pilot project By Jens W. Bonefeld, project manager, ELSAM For some time various technical problems have affected the wind turbines at Elsam’s huge Horns Rev Offshore Wind Farm pilot project. In the autumn of 2003, problems occurred on the transformers of the wind turbines and later production defects have been detected on a large number of generators. The operation of the wind farm can hence not be considered straight forward and valuable experience has been gained in the last year. Elsam’s supplier, Vestas, has acknowledged the problems and is making an energetic effort to solve them and ensure that the turbines return to satisfactory operation. The inclement weather conditions in the North Sea have made the work at Horns Rev difficult, and Vestas is considering it would be more expedient to dismantle all nacelles and bring them ashore to repair them under optimum conditions. This operation is carried out in during the summer of 2004 so that all wind turbines are operational by autumn 2004. Vestas is well under way with the planning of the project and only significant hindrances can stop the completion of the project. A number of turbines and rotors have thus been dismantled and transported to Esbjerg. These turbines and rotors will be inspected and used as preparation for the remaining works. Elsam appreciates that Vestas has demonstrated efficiency in their role as responsible supplier. Vestas has made an effort to ensure that the repairs necessary to make the wind turbines function technically correct are performed as quickly as possible Elsam has a contractual agreement with Vestas on availability and guarantee. Therefore the problems with the wind turbines will only have limited financial consequences for Elsam. Offshore wind power is a business area in embryo. At the end of 2003 the offshore installed capacity only amounted to approx. 530 MW of which approx. 400 MW were in Danish waters. The total installed wind power capacity worldwide is 40,000 MW. However, particularly in Northern Europe and North America there are many ambitious projects in the making. It is expected that approx. 8000 MW will be installed offshore in the period between 2004 and 2008. This corresponds to approx. 15% of the total expected new wind power capacity. ■ 8 Offshore Center Denmark Newsletter ON/OFF 3 - August 2004
A2SEA A/S pioneers in offshore wind By Kurt E. Thomsen, Business Development Manager, A2SEA A/S When the Danish government decided to make a pledge to offshore wind, it was not clear to all how this would actually materialize. In the early 1990´s a number of smaller turbines had been installed in the Baltic and on locations in the sheltered waters of the east coast of Jutland. But now we were talking North Sea, exposed sites, major risks and clearly the number of sites and turbines were to be the driving factor in development of methods and equipment to deal with this new market. In 1999 the founder of A2SEA A/S handed in a patent application for the transport and installation concept which was later to be the backbone of the offshore wind industry, namely the crane ships which have been converted to perform offshore lifting of turbines. The idea was based on the specific environment that prevails on Horns rev and the idea was that if you could cope with the harsh environment out there, you could cope with all possible sites thereafter. The company was formally formed in July 2000 and the first task was to convince the client on Horns Rev—Vestas that A2SEA could actually do what it sets out to do, namely to safely transport and install 80 2 MW turbines offshore within a short time frame. There were only four obstacles to overcome: 1. The system had never been built before. 2. No funds. 3. No offshore experience. 4. Never before actually lifted a wind turbine. The company in so many words started from a clean sheet of paper and developed from there. Fortunately the computer simulations and the scale model tests went very well and the company managed to persuade its client that it could carry out the contractual obligations safely and timely. The biggest vote of confidence therefore came as Vestas put the proposal forward to Elsam Engineering as the system they wanted to work with. And as the contract was awarded, the biggest challenge so far was approached with great vigilance by the three employees of the company, along with a retired naval architect. Within 6 months—albeit more than a month late, the first vessel was converted and ready for testing. Three months of teething problems later A2SEA carried out the first contract—namely the exchange of a blade damaged by lightning on the Blyth Offshore Wind farm, just prior to installing the first turbine on Horns Rev. This was an unusual test, as A2SEA had never before performed offshore work. A2SEA now had to position the vessel on a difficult rocky seabed, with also the tide up to 5 metres this proved to be quite a challenge. A2SEA managed to safely exchange the blade and return to Esbjerg in order to mobilize for the turbine installation on Horns Rev. The turbine installation started off in fairly rough weather but over time A2SEA managed to cope well with waves, swell, wind and currents. A2SEA’s was to load, transport and lift the turbines for Vestas to install and it was incredible to see how quickly all the crews managed to adapt to the new environment they were working in. This was also made easier due to the detailed planning of all offshore operations. Onshore however A2SEA suffered congestion in the harbour, a lesson also taken in well by Vestas and the next projects have all taken this fact into account and made provisions for very large staging areas since. The project suffered bad weather spells, but was blessed by superb weather conditions by July. The installation was finished on August 21st 2002 and this was effectively two weeks ahead of schedule. The two crane vessels stayed at the Horns Rev construction site for hook up and commissioning of the wind farm and these operations lasted the rest of the year and was finished in early December 2002. The contract for the Nysted wind farm was awarded shortly before Christmas 2002 and Bonus used Nyborg harbour as staging area for the 72 turbines. 9 Offshore Center Denmark Newsletter ON/OFF 3 - August 2004
Page 1 and 2: Offshore Center Danmark Newsletter
Page 3 and 4: A Logistic Challenge By Poul Skjær
Page 5 and 6: Additionally the economic part of a
Page 7: Foundation design considerations By
Page 11 and 12: Numerical Simulation of hydrodynami
Page 13 and 14: Loads on wind turbine, tower and fo
Page 15 and 16: Member questionnaire Offshore Cente
Page 17 and 18: accustom themselves to be together
Page 19 and 20: Materials in offshore wind turbine

Read News Magazine (pdf) - Offshore Center Danmark

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?