After the inauguration ceremony, the party, which also includes Fritz H. Schur, Chairman of the DONG Energy Supervisory Board and Anders Eldrup, CEO, will fly back to the mainland to Musikhuset in Esbjerg, where the event with almost 300 guests will continue with speeches, lunch and a press conference.
The world’s largest offshore wind farm supplies its first power
Horns Rev 2 in the North Sea has supplied its first CO2-neutral power to the Danish electricity grid. During the coming season, the wind turbines will continuously be commissioned as they get ready.
Up to production of the first power, the process has been the following:
* Installation of 91 foundations (May-October 2008)
* Erection of the first wind turbine (19 March 2009)
* Voltage from shore to transformer platform (7 April 2009)
* Voltage to row (seven wind turbines) (10 May 2009)
* Production of first power from G3 (13 May 2009)
When the wind farm is completed at the end og 2009, it will supply electricity to more than 200.000 households.
About the Project
Horns Rev 2 is a grand construction masterpiece where many sub-elements have to form a synthesis. Horns Rev 2 is somewhat of a challenge because this wind farm is built furthest offshore compared to any other wind farm in the world, and on top of that it is located in the North Sea – waters which earlier in the Danish history have been known to swallow up many good men. That is why safety is such an important part of the project. The construction period goes from May 2008 to November 2009.
More than 600 people are involved in the project in Esbjerg, and more than 25 different vessels have been hired for the construction period. DONG Energy is the owner and coordinates the complete construction process with seven different sub-suppliers.
The water depth is 9-17 metres and the average wind speed is just below 10 m/s. The average wave height is 1.5 metres – ie 3 metres from bottom to top.
Foundations
Due to currents at the anchoring point of the monopiles in the seabed and thus risk of erosion, stones are dumped on the seabed to limit the movement of the sand. The stones are imported from Norway.
Wind Turbines
A wind turbine consists of a turbine and three blades. The turbines are supplied by Siemens and are of the type SWP 2.3-93. Each wind turbine has a capacity of 2.3MW. With a total of 91 wind turbines the wind farm has an overall capacity of 209MW.
The centre point of the blades will be 68 metres above the sea level. With a blade diameter of 93 metres the total height of the wind turbine is 114.5 metres above sea level. An additional 30-40 metres are below sea level.
All turbine parts are transported to Esbjerg, where the turbine is assembled before it is transported to the offshore bar by ship for erection.
Each turbine has its own IP number which makes it possible to communicate with each wind turbine from shore and from the accommodation platform.
Cables
A total of 70km of cables must be laid at Horns Rev 2. Between each row of turbines cables will be connected from west to east. The cables contain fibre network which transmits communication and control to and from the various wind turbines. All cables are buried in the seabed.
East of the wind farm the 13 rows are connected in the transformer platform. From the transformer platform the produced electricity is transported ashore via a submarine cable.
For the first time in history an accommodation platform is established in connection with an offshore wind farm. This reduces the journey time to and from the wind farm for employees who are to operate and maintain the wind farm during service periods. Due to the size of the wind farm, the accommodation platform is expected to be manned all year round.
The three-level high accommodation platform can accommodate 24 persons at a time and has direct access to the transformer platform via an outer gangway.
Environment
Basically, the construction of yet another offshore wind farm at Horns Rev will have no considerable environmental impact. However, the project will be followed closely, and the animal life in and around the Horns Rev 2 Offshore Wind Farm will be monitored both during the construction phase and the operating phase.
Especially, the common scoters in the entire Horns Rev are interesting, as previous surveys from Horns Rev 1 showed that the common scoters kept away from the wind farm. Meanwhile, it turned out that the common scoters have returned to the Horns Rev 1 offshore wind farm area. The reasons for this are ambiguous, and the food basics for the common scoters will be surveyed in further detail for the Horns Rev 2 area.
Surveys in connection with the EIA report (Environmental Impact Assessment) comprise:
• Birds
• Fish and mussels
• Marine mammals
• Coastal morphology and transport of sedimentation
• Visual consequences
• Risk of collision in ship traffic
• Socio-economic consequences.
Surveys in connection with the construction and the subsequent operation cover:
• Porpoises (during the construction)
• Birds (during operation)
• Food basics for common scoters (razor shells).
All reports are made publicly available upon completion on the website of the Danish Energy Agency. The EIA report as well as a summary report in Danish and English are also available at the website.
Denmark is a pioneer in wind energy, getting about a fifth of its electricity production from wind turbines, which is the highest share of any country’s energy mix.
In the first half of 2009, state-owned DONG Energy generated 9.2 terawatt hours of electricity, with renewables accounting for 1.2 TWh.
The Horns Rev 2 wind farm will be overtaken by other large offshore wind projects.
DONG Energy plans to build a 102-turbine 367-megawatt wind farm in the Irish Sea and it is a partner with E.ON EONG.DE and Masdar in the London Array wind project in the Thames Estuary, the first phase of which will have capacity of 630 MW.
History
Political
In 2002 and 2004, the Danish government and several political parties signed an agreement on wind power and energy savings. One of the elements of the agreement was to construct a 200MW offshore wind farm in Denmark. A possible location was at Horns Rev due to good wind conditions and the relatively low water depth of 8-18m. After a tendering round, the Danish Energy Agency decided that DONG Energy was to construct the Horns Rev 2 offshore wind farm.
Environmental impact assessment
In August 2005, DONG Energy commenced preliminary studies at Horns Rev, and an EIA report (Environmental Impact Assessment) was prepared. The project was designed, and in March 2007, DONG Energy received the approval to proceed with the project.
A reality
The Horns Rev 2 offshore wind farm will be constructed from May 2008 to November 2009, and at the start of the construction in May 2008, the Minister of Environment and Energy, Connie Hedegaard, said:
“One thing we can do in Denmark – and we are unique on that point – we keep the time schedule. Nobody is as good as us, when it comes to planning! It is so important to show the world, what we intend to do. Take care out there, and when the weather is not so well, think of the great contribution, you are all giving to Denmark and to the world. I wish you all the best of luck.”
www.dongenergy.com/Hornsrev2/EN/Pages/index.aspx
