News
08-28-2008
Start of Offshore Wind Energy Exploitation
BARD Group installs Test – Wind Energy Converter Offshore
Hooksiel / Emden The first beat of the ramming hammer marks the commencement of the commercial exploitation of offshore wind energy this Thursday (August 28th 2008). BARD Group, headquartered in Emden (Lower Saxony), installs a BARD VM-type training and demonstration wind energy converter (WEC) in the outer Jade estuary off Hooksiel, near Wilhelmshaven. Beginning next spring, a total of 80 plants of this type will be installed around 100 km off the island of Borkum, to form the wind farm “BARD Offshore 1”. The BARD VM features a hub height of 90 meters above sea level, its rotor diameter measures 122 meters. Its rated power output is five megawatts, enough to satisfy the energy demand of 5.000 families. The WEC is connected to the public grid by a 20 kv cable feeding into the Wilhelmshaven gas and electricity works.
The nearshore WEC will be installed approx. 500 from the shore, between the outer harbour of Hooksiel and the INEOS terminal. This is the first time that the BARD Tripile© offshore foundation will be used. For the installation works, the heavy duty semi submersible barge “Giant 4” is moored near the construction site, carrying two huge cranes. Water depths there range from two to eight meters. BARD Building GmbH & Co KG’s Managing Director, Mr Andree Krueger, who leads the project, explained the installation process to press representatives on Wednesday (August 27th, 2008): “First, we install the three piles of the Tripile”. These are pipes of over 50 meters in length, with a diameter of more than three meters. The piles are initially driven into the soil with a vibrating hammer, ramming is only required for the last few meters.
In mid-September, “Giant 4” will collect the so called transition piece from Cuxhaven, with which the three piles will be connected. This steel construction sports a weight of 470 tons. It was assembled over the past few weeks by BARD Subsidiary Cuxhaven Steel Construction GmbH (CSC). The transition pieces’ three pins will be inserted into the pipes – around 10 meters above sea level – and then “glued“ together using a special cement. The tower will be assembled on top of the transition piece’s centre, towards the end of September the engine nacelle will be installed on top.
According to Manfred Bruhn, Managing Director of CSC, the transition piece is currently undergoing corrosion protection treatment. “We recently commenced operations in our coating hall.” The coating can now be applied irrespective of weather conditions – an important prerequisite for the desired high quality of the anti-corrosion protection. Bruhn states that the anti-corrosion protection is to last at least 20 years: “a ship will receive a new coat of paint in a shipyard every five years”. From late autumn onwards, CSC’s entire production process will take place “under a roof”. Bruhn: “For the first time on this planet, there is a serial production of offshore foundations, and it is here in Cuxhaven. With this innovative technology we shall dispatch up to 100 complete foundations per year.” The new CSC-Production hall is 250 meters long, 45 meters high, and 70 meters wide.
The entire installation process for the WEC off Hooksiel takes place on the water. The foundation is more or less identical to those structures that will be deployed offshore at BARD Offshore 1. “So, the BARD Team can train the co-operation with the other involved parties during the installation process under real-life conditions” says project leader Andree Krüger. Only the 200-ton piles are shorter than those that will be used offshore in 40 meters depth in the North Sea. Likewise, the BARD service crews will be trained for their offshore job on this WEC.
The “BARD VM” will be assembled using a 120 meter DEMAG CC 6800 crawler crane, with a maximum lifting power of 1.250 tons. The so called ramming depth of the three piles is 44 meters. Krüger: Throughout the installation works the legal emission and noise levels will be strictly adhered to, of course!” The ramming process will be over within a few hours only. According to Krüger, the WEC will be complete and operational by beginning of October. The installation process is not overly weather sensitive. “Our logistics- and installation concepts are totally integrated, down to minuscule details, and our WEC is designed exclusively for the tough environmental conditions offshore.” The components are easy to handle and comparatively light. Hence, the installation works will only be interrupted in case of storms.
For the installation of the BARD Offshore 1 wind farm, BARD Group will use its own jack-up vessel “Wind Lift 1” which is currently under construction at a Lithuanian shipyard. Dr. Stephan Bormann, Head of Marketing at BARD Engineering GmbH, considers this a totally new approach to offshore wind farm construction: “Our jack-up vessel is unique.” So far, floating cranes and self-elevating platforms – as used in the oil and gas industries – have been chartered for the installation of offshore WECs. “Wind Lift 1”, however, was specifically designed for the BARD installation concept. This jack-up vessel measures 102 meters in length; it is capable of hydraulically self-elevating out of the water on its four 70+ meter legs, thus offering a safe and stable platform to work on even during strong wind and heavy seas. Its 500 ton main crane has a maximum lifting height of 121 meters. The home port of “Wind Lift 1” will be Cuxhaven.
Immediately after its delivery and acceptance next spring, the vessel is expected to commence installation of the first of 80 BARD VM five megawatt machines in the North Sea. The wind farm will be completed by late 2010. Nontheless, the first offshore – generated electricity will be fed into the grid by mid-2009, when the first WECs will have been completed. Because of the optimal conditions at sea, offshore wind farms generate twice as much energy compared to their onshore-brethren. Dr. Bormann: “BARD WECs will generate ecologically sound and climate-friendly energy for at least 20 years.” Since 2007, BARD operates two onshore prototypes in the vicinity of Emden.