On 11. December at 14.00, the last of the 80 wind turbines at Horns Rev was put into operation by specialists from Vestas. This marked the conclusion of almost 4 months of hectic activity, completing the installation work and testing the turbines.

The commissioning phase of the project was delayed by approx. 1 month in relation to agreed schedule.

During this time, Vestas has had up to 50 fitters at the rev, where the two crane-vessels from A2SEA, Ocean Hanne og Ocean Addy, have functioned as hotel-ships. 4 – 5 chartered transfer boats have transported the fitters around between the turbines, where they have been fitting cables and testing the turbine’s mechanical and electrical systems.

After commissioning, the turbines can be put into normal operation, however experience shows that some minor faults and alarms can arise during this phase. These must be rectified on the turbines before full operation can be achieved. To date, the production record from Horns Rev has been approx. 110 MW with 50-60 turbines in operation simultaneously.

The advanced remote control equipment is connected to all the turbines in the park via fibre optic cables. So that, Vestas og Elsam have via the remote control equipment, direct access to the turbine controls and can from land respond to information and operational data from the turbines.

There remains as yet some outstanding work and repairs to be completed – primarily concerning the longevity of the turbines. This work is expected to be completed in spring 2003. Moreover, one or two of the blades on the park’s turbines were found to be damaged by lightning during a thunder storm in the area, in the autumn. Replacement blades are expected to be installed by the end of December.

The turbines shall in accordance with the agreement between Vestas and Elsam demonstrate a stabile operation for a prearranged period of time. When all the turbines have completed this trial operation – both singularly and in groups – the turbines can finally be taken over and commercial operation can commence. This is expected to occur at the start of 2003. 

While Vestas has been working hard to finish the installation and commissioning of the turbines, MT Højgaard has been carrying out extra laying of stone as a security measure against corrosion around the submarine cable casings where necessary. Approximately 45.000 ton of this additional stone has been laid.

On 11. December at 14.00, the last of the 80 wind turbines at Horns Rev was put into operation

Horns Rev - 80 Wind turbines - 160 MW.

The turbines shall demonstrate a stabile operation for a prearranged period of time.

Besides the service technicians, who handle the daily work out at the wind turbine park, a staff has been assembled, who shall manage and support the service work. This involves amongst others, tasks relating to the coordination of transport by boat and helicopter, monitoring of the operational status of the turbines and registration of the work carried out.

The standard mode of transport to the park will be helicopter.

26 persons are currently trained to to be hoisted down to the turbines from a helicopter.

Experiences

Naturally, in the course of such a large and innovative project as the Horns Rev-project, an extensive list of experiences and valuable knowledge are bound to be gained.  We asked  Elsam’s project leader on Horns Rev-project, Jens W. Bonefeld, to give a brief introduction to the most important of them.

By Jens W. Bonefeld

As the Horns Rev project is about to enter its final phase, it provides an opportunity to pause and reflect upon the experiences gained.

The planning for such an innovative project has been very important. The project has benefited from the fact that parallel to the required environmental surveys there had been sufficient time to gather the prerequisites for climatic and soil conditions. This has provided a good basis to undertake preliminary engineering evaluations of the construction, implementation and operation of the park. 

Moreover, this has provided a platform for defining some of the implementation and contractual frameworks for the contractors and suppliers. Their contribution to the process has led to the overall success of establishing the park. Elsam’s suppliers and contractors have reacted well to this good basis by working whole-heartedly towards the success of the project. The suppliers and contractors have experienced that the project has placed great demands on the planning of logistics and equipment selection and that it has also been necessary to adjust methods and equipment concepts. Having said that, it can be noted in contrast that a project with 80 identical units has enjoyed a lot of repetition and that the learning from this has been especially impressive over  the summer

Elsam chose to coordinate the work by drawing up independent contracts for the individual project groups concerned (multi-contract principal). This meant that following up on the time schedule and the technical and implementation interfaces was critical. Experience has shown that this demands great vigilance and care to succeed.

Seen from Elsam’s side, the task of coordinating the work at Horns rev has also been immense, concerning safety, traffic control and diving work. In this area, much valuable experience was gained which can benefit other projects. In this respect, the collaboration with the public authorities has played a great role – this type of project also involves new aspects for them.

The Horns Rev project has opened up a new business area within the energy industry and the emergence of opportunities for continual development. Elsam as an energy producer will pursue these opportunities and is already involved in similar projects around Europe. The suppliers and contractors will similarly pursue these opportunities. The wind turbine manufacturers are seeking to increase the size of their turbines and similarly adapting them to operating conditions. Contractors are also looking at possible investments in equipment which could be adapted to suit special types of projects.

However one must not forget, that there still remains a great challenge in the operation and maintenance of the park for many years to come, as long as the production is high and the maintenance costs low. This chapter is just beginning. 

Elsams project leader on Horns Rev-project Jens W. Bonefeld.

Important events of the Horns Rev Project

V80/2 MW prototype turbine erected in Tjæreborg		5. December 2001
First foundation arrives at Esbjerg Harbour		13. February 2002
First fundament pile driven		30. March 2002
Eltra's transformer module placed at Horns Rev		16. April 2002
First turbine erected		7. May 2002
First cable laid in park		19. May 2002
First turbine in operation		29. July 2002
Transition piece fitted on the last foundation		3. August 2002
Last turbine erected		21. August 2002
Last cable laid between the turbines		23. August 2002
Blades damaged on V80/2 MW prototype turbine erected at Tjæreborg		4. November 2002
All the turbines in operation		11. December 2002

On Monday 4. November at approx. 9.00 a.m. the new 2 MW offshore test wind turbine i Tjæreborg was damaged. The wind turbine is a  prototype of the 80 wind turbines, which Elsam has erected at Horns Rev. After the incident Vestas carried out a through investigation into the cause of the damage. They concluded that the fault occurred in the turbine’s safety system as a result of a human error related to work carried out on the turbine on the 24. October 2002. The fault was restricted to this single wind turbine. Shortly after the incident, the turbine was fitted with new blades and is now back in operation.   

Elsam has just erected the largest wind turbine in Denmark - a Vestas V90/3 MW turbine on a “bucket foundation” off the harbour of Frederikshavn. The turbine is a further development of the 2 MW offshore turbines Elsam has employed at Horns Rev. The wind turbine has a rotor diameter of 90 M and an overall  height of 125 M. Altogether there are 4 offshore turbines on the site, giving a total output of 10,6 MW. The turbines are supplied by Bonus, Vestas and Nordex.  The other three turbines are erected out  from the harbour in Frederikshavn, on a traditional foundation and are expected to be in operation by June 2003.

3 MW Vestas turbine mounted on a “bucket foundation” at  Fredrikshavn

On a site by Aalborg østhavn, Elsam has just erected the latest offshore turbine from NEG Micon. The turbine is a NM92/2750 type, which is NEG Micon’s largest model to date. The 2,75 MW turbine has a total height of 115 M and a rotor diameter of 92 M and is a newly developed offshore model. 

Elsams 2.75 MW offshore turbine under erection by Aalborg Østhavn

This is the last regular newsletter to be sent in connection with the Horns Rev project. In the near future, the park will go into commercial operation and pass over to Elsam’s departments for operation and maintenance of wind turbines.

However, a constant registration of the park’s environmental significance will still continue. We will continue to make the ongoing reports available here on the project’s home page. Moreover, we cannot rule out the need for further newsletters concerning environmental surveys pertaining to the project, at a later date.

Elsam A/S
Overgade 45
DK-7000 Fredericia
Phone: +45 76222000
Fax: +45 76221962
www.elsam.com