Onshore wind farms have become a familiar sight for many in recent decades, and certainly look impressive once in situ and turning. Even more impressive, for those of us with an eye for abnormal loads at least, are pictures showing their constituent parts making their way down the road.
Halifax-based heavy haulage operator Collett & Sons is one of the companies that specialises in wind turbine deliveries, but it doesn’t just supply the equipment and drivers to physically do the job. Collett’s has an in-house consultancy team, offering route surveys and reporting on access to sites at the planning stage. Renewables director Jack Collett explains what happens behind the scenes.
“The developers can start planning as much as five years in advance,” he tells us. The very first thing needed to build a wind farm is planning permission, the application for which involves an environmental impact assessment. That includes a transport section, which is where our consultancy team at Colletts can come in, looking at access to the proposed site.
“There’s always more than one way to skin a cat,” Collett says. “So our analysis is quite comprehensive, and some solutions to enable access may have more financial impacts than others.” The problem is that all the easily assessable sites have already been developed, so the remaining sites are inevitably going to be harder work. “This has led to the wind energy industry demanding the development of new and improved trailer technologies, to enable access to the more difficult sites.”
At this stage, however, the actual haulier hasn’t been appointed. That scope is usually done by the supplying manufacturer of the turbine rather than the developer, and there’s no guarantee that Collett’s will get the job. Some manufacturers supplying the turbines want to be impartial, so they often bring in third parties to do a computer-generated route survey – something that Collett’s department is very capable of doing itself.
“When it comes to execution, we tender for the contract and, if successful, we generally get around six months’ notice to get ourselves organised, although the more time we can get, the better for planning and permitting purposes,” Collett explains. “That includes having to apply for BE16 Special Order permits to move the more onerous components – those with dimensions that exceed the limits of a standard abnormal load permit, which is a six- to eight-week process.” Map-based planning can only get an office-based consultant so far. To really know whether a route will work, you also need to know how the loaded vehicles actually steer and manoeuvre. “Before a project starts, we like to do a test drive with an empty trailer, extended to replicate the most onerous component,” Collett says, an approach that has now become mandatory for sites in Scotland. “That’s usually the blade, because of its overall length.”
Collett & Sons is currently using Super Wing Carriers built by Nooteboom and Wing-Max by Faymonville to transport turbine blades, which have been specifically designed for the task. But as wind turbines continue to increase in size, these will become obsolete. “We’ve a project next year that will feature 80m blades,” Collett explains. “So we’ve had to invest in new blade transport technology, which is a clamp and bogie system, because of the sheer length.”
This is similar to the tower transport method, in which a steered dolly is placed under each end of the load itself and the component effectively becomes the body of the trailer. Using standard blade trailer technology for 80m blades and beyond poses stability issues, as well as making it far more challenging to cope with undulations in the road alignment – just one of the things a route survey is designed to look for.
“Third-party land requirements are a big topic,” Collett says. “So when we arrive at a junction, or a problematic pinch-point, we have to check whether we need to cross highway boundaries onto third-party land.” Arranging that can involve a lot of negotiation with landowners, but it’s not something Collett & Sons has to do as the haulier. “We simply highlight it in a report,” he assures us. “It’s the developer that does all the nitty-gritty and negotiations.”
Collett & Sons also assesses the need for street furniture removal and tree pruning, as well as overhead structures like bridges and low-hanging cables when the load will be high. This often falls into the lap of the haulier to process, and unfortunately there’s no standard method, so it’s different on every project.
Removing street furniture in particular isn’t always easy. Lamp posts can be a challenge, for example, simply because the road needs to remain lit to a certain luminosity at all times, regardless of the length of the job. Some parts of the country see a lot of abnormal loads, so their signs and lights are designed to be on sockets and can be slotted in and out on a regular basis. Others, however, are not. ”Coming out of the dock at Glasgow there’s a junction we have to manoeuvre along, but the council won’t make a permanent adjustment,” Collett says. “It has a traffic management team that has to attend, so there’s extra cost involved every single time this furniture is removed.”
Telecommunications and power companies can be difficult to deal with too, we’re told – time-consuming and long-winded, mostly. Until recently, high loads have been a rarity on these types of projects, but that is starting to change thanks to a new kind of trailer Collett & Sons has invested in – a BladeLifter. Built by German heavy transport equipment specialist Scheuerle, it tilts the blade vertically, reducing the vehicle length and required turning circle.
“We’re moving 65m blades at the moment. They’re tilted to 60 degrees, so they’re approximately 60m high,” Collett tells us. “The route that we’re taking has had to have power lines and telecommunications lines moved and much more – it has taken months of planning and rectification work!”
The other limitation is the weather. “It’s certainly more difficult because the blades are designed to catch wind, so you can only use a blade lifter when it’s not too windy, which limits the periods of operations,” he points out. “It’s also a lot slower travelling and manoeuvring. But the advantage is there’s less need for the negotiations over using third-party land, and that’s a huge financial and time benefit to the developer.”
The actual blades, while long, aren’t as heavy as you would imagine: current weights vary from 15 to 20 tonnes each. But they’re no good on their own. “The turbine also requires other components such as the towers that come in several sections, usually three or four per tower, although five section towers are being produced now as turbines are getting larger,” Collett explains. “They vary in length from 10m to 30m and they taper, so they start usually at 4.3m diameter then taper down to around 3m at the top.”
Tower sections travel on purpose-built transporters, which in Collett’s case are built by Scheuerle, Nooteboom and Doll. The flange at each end of the section is attached to a clamp; then there are multiaxle bogies at both front and rear. Add in the truck itself and a 30m tower section turns into a 50m vehicle overall. In this country we’re restricted by the height of our motorway bridges, but that doesn’t stop manufacturers from pushing things closer and closer to the limits.
Weights for tower sections are inevitably rising as well, currently ranging between 40 and 90 tonnes apiece. Then there are the nacelles, which contain the actual generators that sit on top of the towers, along with the gearboxes and drivetrains. “They can vary from 60 tonnes up to 80 tonnes, but the bigger the turbine gets, the heavier its components become,” Collett tells us. “We’re seeing that now for the new generation of turbine we’ll be delivering next year,” he adds. “They’ve a nacelle that’s 86 tonnes, plus a drivetrain that’s 95 tonnes.”
At the moment, all wind turbines used in this country have to be imported, and the DfT dictates they must use the closest port to each project. The majority of onshore wind farms are up in Scotland, although there is starting to be more interest in Wales, too. This means ports like Glasgow, Grangemouth, Inverness and Ayr see a lot of movements, although smaller docks are used as well. “We’ve got a couple of projects next year up near Thurso, so we’ll be using the port of Scrabster,” Collett says.
This is, of course, all aimed at keeping the disruption caused by such large loads travelling on public highways to a minimum. Deliveries are often made at night, to avoid attracting complaints from local residents, but that isn’t always possible. “We’re delivering one project in the Scottish Borders at the moment with the BladeLifter, and that’s daytime deliveries only, so it’s causing some minor disruption,” Collett says. However, the job is planned like this with good reason. “When you’re travelling 60m in the air, you’ve got to be able to see what’s happening in your surroundings!”
Ultimately, though, the number of wind turbine movements is only going to increase. Not only are larger structures like this being built in ever more areas, but existing equipment is starting to be replaced as well. “It’s usually a 20- to 25-year lifecycle, so some of the turbines I saw being erected when I first started at the company are beginning to be decommissioned now, and they’re repowering the site with larger more efficient turbines,” Collett tells us. “So hopefully that’s a cycle that will continue.” Theoretically then, neither Jack Collett nor Collett & Sons need ever run out of work.
“Hopefully not,” he says, with a grin.
- This article was first published in the 22 February issue of Commercial Motor.
