By Petra Barnby
‘They’re beautiful,’ breathed a bearded wind farm enthusiast as he spotted the shape of a turbine appear from the mist on the horizon.
A cloud of wispy grey lines easing out of the grey-blue sea mark the first sighting of the offshore wind farm. There is a rustle of excitement from onlookers as the scale slowly becomes clear – the diameter of the blades is 90 metres across, the towers rise 60 metres out of the sea and you could lie down along the width of a blade. The only noise as our boat draws up underneath a turbine is a very heavy sounding ‘wooph’ as the six ton blade swings round. Apart from that, a big silence surrounds this energy factory.
The 30 wind turbines at Kentish Flats off the Thames Estuary provide enough energy for 50,000 homes. They look surprisingly at home at sea – there is a serenity and peacefulness about their understated orbital business that fits in with the drab North Sea scape.
This small gathering of turbines makes up a small part of the UK’s effort to meet its legally binding target of providing 15 per cent of our energy needs from renewable sources by 2020. The lion’s share of these renewables will come from wind power, representing a ten-fold increase on current levels up from today’s 0.6GW to 33GW.
Duncan Ayling, head of offshore at the British Wind and Energy Association (BWEA) says now is the time for UK offshore wind energy.
“It is boom time. The government has got these targets. There is no alternative,” he said.
Just six months ago it looked like the writing was on the wall for offshore wind power in the UK when our only wind turbine manufacturing plant in the Isle of White closed its doors putting 425 people out of work. But a combination of one of the most attractive Government incentive schemes for new farms in Europe, and a very blustery environment, mean the tide is turning for the future of the business in the UK.
But the industry is again looking up. The government’s Renewables Obligation Certificate (ROCs) scheme – which requires energy suppliers to present certificates to prove that a certain amount of their energy comes from renewable sources – has succeeded in boosting the industry. The price of the scheme is ultimately picked up by the consumer as suppliers factor the cost into their energy prices.
There was news this month that Centrica persuaded private investors and banks to invest £460m into a wind farm off the coast of Skegness. Meanwhile, the membership of the BWEA has jumped from 300 to 500 member companies in the space of two years. The owners of Britain’s seabed, The Crown Estate, are gearing up for their third and largest round of wind from licensing and there is talk that 40 big businesses are vying for the sites.
And plans to build the London Array in the Thames Estuary are on firmer footing after new investors appeared to save the project. When its 341 turbines are installed it will be the biggest wind farm in the world, covering 90 square miles and generating electricity for 750,000 homes.
If all this works out, and the government gets its way, there could be 5,000 turbines peppered around the UK coast capable of powering 18.5m homes in 10 years’ time.
Challenges of offshore
This is no small order and investors are nervy of the long list of things that can go wrong with offshore wind farming.
The first stumbling block is that offshore turbines are between two and three times as expensive to install as onshore ones. But onshore is increasingly less realistic with the problem of nimbyism stalling projects indefinitely (people even complained about the farm at Kentish Flats which is located five miles out at sea) and a lack of space – there are already 254 onshore wind farms in the UK.
Surprisingly, one of the many issues of having turbines at sea is a lack of space – there are only a few small pockets of seascape which are the correct depth, are far out enough, but not too far out, and that will not disrupt the environment or shipping routes.
Then there is the technology and logistics. Whichever way you look at the debate raging over the future of our energy supply, offshore wind power is a particularly expensive and unwieldy solution. Driving the thousands of turbines needed into the seabed will require a vast amount of money, metal, concrete and cables. Each turbine weighs 500 tonnes, nearly twice as heavy as an onshore turbine, because of the 250 ton steel pile needed to secure it.
Another concern is that the application system for investors may not be able to cope with the influx of interest which is going to peak in a four-year site application window from 2012. There will then be the challenge of bolstering the supply chain – specialised boats with cranes, undersea cabling devices, new docks, upgrades of onshore energy grids and skilled manpower are all going to be needed in droves, preferably provided from the UK.
There is also the small problem of turbine technology which, despite constant improvements, is not perfect. The question remains – how to maintain the turbines in heavy seas without putting engineers at risk.
And to top it all off, the price of installation has gone up in recent months due to rising supply chain costs and steel prices but it is hoped that an increase in demand brought about by the Government’s incentive scheme will bring in more suppliers to drive prices back down.
William Young, lead of the Wind Insight Team at renewables consultancy New Energy Finance, the remaining challenge will be for investors to get to grips with the tricky but doable business of installing turbines at sea.
He said: ‘As well as capital, investors need to be able to run major offshore construction projects. What these companies understand is the significant political support at both national and European level for offshore wind which has meant that despite multiple challenges capital is being committed to build these projects, though with justified caution.’
But despite these difficulties, offshore turbines are super-efficient, producing up to 25 per cent more than onshore ones. At sea there is a more constant and pure supply of wind because it has been disrupted by trees and hills. One of the biggest turbine manufactuers, Vestas, has just announced it is to launch a turbine which is twice as powerful – and big – as its current turbines.
The argument that offshore is too expensive takes away from the fact that it must be part of the diverse mix of energy production in this country if we are to cut carbon emissions. Investors must take a long-term view – according to the Department of Energy and Climate Change, offshore wind has the potential to provide the UK with an estimated 70,000 new jobs and £8bn in annual revenues.
Peter Madigan, British Wind Energy Association’s Offshore Renewables Development Manager said: ‘There is a potential for hiccups along the way. Industry has a huge appetite for this opportunity but we shouldn’t pretend it will be easy.’
How do you install a wind turbine in the sea?
The turbines are installed by first hammering a vast steel pile into the seabed. A floating crane then lowers the turbine tower onto the pile and the blades and their turbine are installed on top. The blades are designed to swivel according to the wind intensity in order to obtain optimum power generation. The whole head swivels too, so the blades always face into wind. A special seabed plough then creates a trench for the power cables which run to the nearest onshore grid. The turbines are constantly maintained by a call-out boat full of engineers who zip up and down the towers in lifts to sort out any glitches.