Engineering news
Submarines and cablecars were among the ideas submitted to a Carbon Trust competition aimed at finding ways of accessing remote offshore wind farms during stormy and inclement weather to improve the economics of renewable energy.
The trust whittled 450 concepts down to 13 winners which will now receive up to £100,000 in funding each with the aim of commercialisation. The winning ideas included a boat with suspension, a giant robotic arm and a vessel resembling a seahorse. They are intended to enable the transfer of workers to “round three” windfarms, which will be much further out to sea than their predecessors.
Today’s offshore windfarms are typically less than 25km offshore in relatively benign sea conditions, and consist of up to 100 turbines. Maintenance is possible in boats about 90% of the time when wave heights are up to about 1.5 m. The new round three offshore wind projects will be as far as 300 km offshore in rougher sea conditions, and may consist of as many as 2,500 turbines. At these sites, today’s access systems would only allow transfers about 210 days a year. The aim of the competition is to find concepts that can be commercialised to make transfers possible for a minimum of 300 days a year. It is thought doing so could increase the revenues of wind farms by as much as £3billion.
Among the 13 designs shortlisted are a giant robotic arm for transferring workers and equipment to the turbine base; a boat that uses suspension inspired by Paris Dakar-winning rally cars to remain stable for the transfer; a “seahorse” vessel consisting of a towering keel that minimises movements in the ocean swell; and a giant harbour mother ship that would act as a base for personnel for weeks on end, dispatching smaller daughter craft to access the turbines.
Jan Matthiesen, offshore renewables acceleration manager at The Carbon Trust, said: “Some of the ideas that we received were crazy but the majority were credible. We needed to have a closer look at most with our partners which included many utilities developing offshore wind.
“We had an idea where you create some harbour or structure around the turbines to provide alee with wave breaking devices and so on, but the cost factor became quite prohibitive, a penalty.
“We looked at different technologies: transfer systems, launch and recovery, and at vessels. Vessels needed to move at certain speeds from turbine to turbine but they also needed to be very stable when not moving. Normally boats when moving are stable but less so when stationary. This sea-keeping aspect was important.”
The Carbon Trust is leading the development programme in collaboration with eight UK wind farm developers – E.ON, DONG Energy, Mainstream Renewable Power, RWE Innogy, Scottish Power Renewables, SSE Renewables, Statkraft and Statoil – with the aim of reducing the costs of offshore wind.
It is thought the global market for these types of technologies could be worth £2billion. Fifty per cent of this, the trust believes, could be in the UK alone due to the harsh conditions in the North Sea.