Offshore windfarms have a growing role in
cutting UK carbon emissions, but they're expensive. We've selected
five innovations that could help cut costs, from a new
Royal Society journal special issue exploring the
cutting edge of wind power.
Cost-cutting innovations are important because a
growing share of the UK's electricity is generated by offshore
windfarms. The UK has 4,042 megawatts of
offshore wind capacity, more than any other
country in the world.
These windfarms supplied 3.6 per cent of the
UK's electricity in the
12 months to October 2014, a tripling in
three years. The amount of electricity we get from offshore wind is
expected to at least
double by 2020.
Offshore windfarms are attractive to politicians
because they're typically built out of sight, plus the wind blows
harder and more consistently out at sea. The snag is that they're
expensive, nearly twice as costly as onshore windfarms per unit of
electricity generated and 50 per cent more costly than nuclear
power, according to a
recent EU study.
The expense is largely down to the difficulty of
installing and maintaining large wind turbines able to withstand
This week the Royal Society has published a
special journal issue devoted to offshore
innovation. It has 16 papers covering everything from designing
better turbines using computers and miniature models to cutting the
cost of installation and maintenance through remote sensing. Here
are five ideas from the special issue that caught our
Screw-in turbine foundations
Ever-larger offshore wind turbine designs pose a big
engineering challenge. They typically have to be secured in deeper
waters, against larger waves and able to withstand heavier loads
from their bigger sails. This strains the limits of standard
'single pile' foundations.
Developers are starting to use a
range of new foundation designs, from
tripods to floating platforms. But
one of the Royal Society papers suggests a
novel option: helical piles. Instead of driving a single hollow
steel tube foundation into the ground with a pile driver, helical
piles are essentially giant screws that would be screwed into the
There are already used on land for some
applications and offer several advantages, the paper argues. They
can also be 'unscrewed' when the turbine reaches the end of its
life, easing decommissioning.
The paper says they're stronger and suitable for
a wider range of soils. Screw-in piles would also bypass concerns
noise impacts on whales and dolphins caused
by pile-driving traditional foundations.
The only problem? Screwing the piles in without
spinning the installation boat round and round. One answer may be
to screw two helical piles in at one, in opposite