August 27, 2018
Anniversary for a pioneer: BARD Offshore 1, Germany’s most productive offshore wind farm, has been in operation for five years
BO1, the first and 2017 most productive offshore wind farm in Germany is completely connected to the grid since September 2013.
80 wind energy generators of the 5 megawatt class reach a nominal capacity of 400 mega watt - this equals the energy consumption of more than 400,000 households.
BARD Offshore 1 was supported by the European Commission within the scope of the European Energy Programme for Recovery (EEPR).
The offshore wind farm BO1 is located approx. 100 km north of the isle of Borkum in the German North Sea and comprises an area of approx. 59 square kilometres.
Location: 90 kilometre north of the isle of Borkum
Area: 59.2 square kilometre
Water depth: up to 40 metre
Turbines: 80 BARD 5.0 wind energy converter of the 5 megawatt-Class
Rotor diametre: 122 metre
Hub height: 90 metre
Total height: 152 metre
Total power: 400 megawatt
Production: 1.6 billion kWh per year (supply of approx. 500,000 households with green energy)
Start of construction: April 2010
First power input: Dezember 2010
Commissioning: September 2013
Total investment: more than 1 billion Euros
5 MW Offshore turbines of class 1c with a rotor diameter of 122 m
three roter blades made of plastic on epoxy resin basis with an electronic pitch system
drive train with main bearing and hollow rotor shaft
three level gear box und six-pin double feeded asynchronous generator
Wind turbine and tower segment are mounted on a tripile foundation consisting of three piles connected trough a transition piece.
Total height of a single pile varies between 84 and 91 m, depending of the exact location within the wind farm.
The zylinder shaped piles are hollow and its diametre is 3.35 m. The thickness of the walls varies between 40 and 120 mm depending on the soil conditions and the location within the farm.
For errection, the piles are hydraulically hammered into the mud by using the especially desgined Pile Guidance Frame (PGF).
In the next step the cross-bracing is laid onto the piles from above and the junctions are grouted. The grout material is a special concrete which is molded into the space between the bottom end of the cross bracing's pins and the top end of the piles.
The grouted connection is optimised through shear keys.
Advantages of the tripile foundation over tripod, mono pile or jack-constructions are:
Especially designed for huge water depth and far offshore installation.
Simple and easy to errect construction, most parts of the errection occur above the water line.
Low maintenance effort, most work to be executed above the water line.
Easy to adjust to different locations (water depth, load, etc.) through change of the pile geometrics.
Farm external grid connection:
Farm internal grid connection:
Converter platform BARD 1:
In the context of the approval process of a wind farm in the German exclusive economic zone the potential issues affecting the sea environment have to be examined. Furthermore it is required by law to execute an environmental impact assessment. To fullfill theses two obligations a so called Environmental Monitoring is installed. Method and range are determined by the permit authority, the Bundesamt für Seeschifffahrt und Hydrographie (BSH).
All phases of a project's lifecycle (planning, construction, operation, decommissioning) are included within the Environmental Monitoring and ranges each within different time frames. In the planning phase data of a minimun of two years needs to be included, in the operating phase a minimum of three years. This periods can be extented by the permit authority BSH up to a maximum of five years.
Subject of protection, to be examined in the monitoring, are benthos, fish, avifauna, bats and maritime mammals. Due to the long time periods and big efforts costs for environmental monotoring are quite high, several million Euros.
For erection of the offshore wind energy generator it is necessary to fasten its foundations in a water depth of up to 40 metres. This is performed by driving the piles between 30 and 40 metres into the seabed. During the pile driving noise emissions of approx. 175 dB occur in approx. 750 metres distance. As this maritime underwater noise can damage maritime creatures, the usage of noise protection actions are obligatory.
In 2011 the so called Offshore Test 1 (OFT 1) was performed within the wind farm BARD Offshore 1 and a novel noice protection system was tested. A Small Bubble Curtain (SBC) was used, which produces small bubbles for noice protection during pile driving next to the piling pipe. It has turned out that noice emissions have been clearly reduced by using the SBC.