Dutch Build Towering Wind Turbines Out at Sea
Date: 04-Sep-07
Country: NETHERLANDS
Author: Alexandra Hudson
That is why a new Dutch wind farm is being built so far out
to sea it is barely visible on the horizon, reducing the visual
impact of its 60 turbines to virtually nil whilst at the same
time harnessing higher offshore wind speeds.
Offshore wind farms are likely to appear more and more
frequently off European coastlines as governments seek to
increase their use of renewable energy without angering their
citizens by placing giant turbines on their doorsteps.
The 383 million euro (US$522.3 million) Q7 wind park
development, 23 km (14 miles) from the Dutch North Sea coast, is
the farthest offshore wind park anywhere in the world, and its
developers Econcern and Eneco Energie say a further five to 10
such wind parks will likely follow in the next few years.
"Q7 will contribute enough electricity for 125,000
households, but it is also a learning process. We are learning
how to build these wind farms, how to organise the supply chain,
and how to manage and operate them," said Bernard van Hemert,
one of the wind farm's engineering directors.
"Most campaigns against turbines are based around the noise
and the visual impact, and these have been reduced by going
offshore. It is more expensive to do it here than to do it on
land, but we have all agreed we don't have enough space on
land," said van Hemert.
Blessed with shallow sandy soils around their coastline,
Dutch engineers say the foundations for the turbines can be
hammered 25 metres (82 feet) into the ground in just a matter of
hours, although there are myriad other challenges.
The proportions are breathtaking. The turbines extend about
98 metres (320 feet) from the ocean, with three sharp narrow
blades, each 40 metres (130 feet) long.
It is hoped that when they start rotating in early 2008 they
will cut carbon-dioxide emissions by 225,000 tonnes, helping the
Dutch to meet a target of 20 percent renewable energy use by
2020.
TRICKY LOGISTICS
The turbines are so massive they can only be transported by
sea and there is just one factory in Europe which can weld and
construct the 4.5-metre-diametre piles, which must be first
driven into the sea to form the base of the turbines, van Hemert
explains.
"It is a huge logistical operation which requires lots of
space. There are only a few crane vessels which can handle those
huge structures and hammer them down."
"But bringing up the cables is the most challenging for all
offshore wind projects."
Expert divers are helping to fit the electrics.
Developers have also had to ensure that the wind park is
well away from busy shipping channels.
"Studies in the United Kingdom have shown that there can be
some radio interference but in the situation we have here it is
completely safe and there is no risk of confusion or reduced
visibility for vessels."
Jim Mollet, chairman of a Dutch group campaigning against
wind energy acknowledges off-shore wind farms have some benefits
over land-based wind turbines.
"They can be a better solution. But the problem is people
tend to believe they are an entire solution. We think the vast
sums spent on wind farms would be better spent on research and
innovation in other energy sources."
Wind farms cannot generate the sheer amounts of energy the
continent requires with cost or space efficiency, he added.
