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Decommissioning Vindeby Offshore Wind Farm – the world’s first offshore wind farm

WIND FARM When the world’s first offshore wind farm,
Vindeby, was commissioned in September 1991 – it provided clean and green energy
to almost 2,200 households. With its 11 wind turbines and
a total capacity of five megawatts – – located northwest of Lolland
in the southern part of Denmark – – it marked the first step taken
to reap offshore wind potential. Despite the wind farm’s modest size, it has help paved the way for large scale Danish exports and job creation enabling Danish suppliers to gain a strong position in the industry. Vindeby has been a really good
proof of concept for offshore wind. It lasted 25 years. And when we decided to take it down – – we looked at the technical
and the financial aspects. And as they were found to be worn out,
especially the gear boxes – – the decision was pretty easy, based
on the financials in the project. Wind power is non-polluting electricity generation. Bringing it offshore offers
countless siting possibilities – – and up to 50% more energy generation
than an onshore wind turbine. Which in turn increases its environmental value. But it was challenging moving
the wind turbines offshore. They had to be protected from corrosion. So they were equipped with dehumidifiers,
heat exchangers and anti-corrosive paint. This was the recipe for success.
The solution is still a basic principle. But now the turbines are being taken down. After more than 25 years, which
is longer than anyone dared hope for. With water depths of 2-5 metres – – all work must be carried out
using relatively small vessels. We’ve put great emphasis on
minimising the environmental impact – – in relation to the onshore residents
and the area’s animal and plant life. In 1991, the wind turbines
were lifted into place in one piece. Today, we remove one blade, then
the nacelle and the remaining blades – – and finally the tower,
and everything is loaded onto a barge. This is done with a mobile crane
mounted on a jack-up vessel. The foundations are concrete gravity foundations. They were cast on shore and sailed out
to be placed on the sea bed. But because the foundations
weigh up to 480 tonnes each – – they are cut into smaller parts. This is done with milling equipment and hydraulic demolition shears. The concrete elements are collected and
placed on a barge for transportation. At the same time as the foundations are broken down – – the cables between the wind turbines and to the farm are removed. Except for one turbine, donated
to The Danish Museum of Energy – – all the components will be sent
to Nyborg Harbour for reuse. As spare parts for other turbines – – or as recyclable material
for recovery companies. Some components are sent for testing. The Technical University of Denmark
and various companies – – will study the life time
of the wind turbine components. The concrete from Vindeby
is of interest to me. Because it’s 25 year-old concrete, which
has been exposed to a marine environment. So I can make an analysis
of the concrete – – which can tell me something about
the durability and chloride ingress. And then we can refine our models
of chloride ingress in concrete – – that we use to predict the
service life of concrete structures. Technicians doubted whether the
turbines could withstand sea water. But Vindeby exceeded all expectations. Vindeby has been important, as it was
the world’s first offshore wind park. And it has spurred the industry to look
to the stable winds of the sea. It has been a remarkable development
from a small demonstration project – – to being the cradle for
where we are today. Vindeby
marked the first step on the journey. And since then, offshore wind farms
have become genuine power stations. DONG Energy’s upcoming offshore
wind farm, Hornsea Project One – – will be able to deliver green energy
to one million UK homes in 2020. But it all started with Vindeby.


  1. Herongate 1 Author

    Very good news that you are keeping one turbine as a museum piece, this was the birth of our green future. If there is a future. Our children will remember Vindeby.


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