Contracted by a market leading wind farm operator to refurbish two wind turbines in Central Victoria, Johnson & Young Cranes (JYC) provided an innovative, cost-saving, emission-reducing alternative to the historical method of undertaking this scope of dual lifting work with two lattice boom crawler cranes: wind farm dual lifts with two hydraulic mobile cranes. Engineer John Humphries talks technicalities, fleet mobilisation, logistical challenges and the performance of JYC’s Liebherrs.
As of October 2022, there were 94 operational wind farms in Australia playing host to over 2,700 wind turbines. Currently, the wind accounts for just over nine gigawatts of energy per year. By 2035, that number is expected to hit 32 gigawatts per year.
And so, with a large, forecasted growth in the wind industry comes the need for equipment capable of erecting, maintaining, and repairing the turbines themselves.
Based out of locations in Melbourne’s North and Southeast, JYC – ‘Team Orange’, as it’s colloquially known – performs a range of lifts in the construction and renewables industries across Australia.
JYC runs a fleet of over 30 machines ranging from its three-tonne mini-Maeda through to its monstrous 800-tonne capacity Liebherr mobile cranes. In and among those cranes are two 650-tonne Tadano crawler cranes and three 350-tonne crawlers operated through a joint venture, and a range of supporting equipment including 13 prime movers and 30 trailers.
So, when JYC’s valued client presented the company with an opportunity to participate in this unique project, the JYC team knew it held the perfect fleet capacity to complete the project at hand: the restoration of two wind turbines.
JYC was contracted by a large wind farm operator to undertake major component exchanges on two wind turbines. To achieve this, the Melbourne-based crane hire company needed to remove the three blades, the hub, the gearbox and drivetrain, to swap the required parts, and then replace everything it removed from the turbine.
The heaviest item the crane hire company would be lifting weighed in at nearly 40t. On the other hand, however, wind turbine blades – despite falling well within the selected cranes’ capacity – are designed to catch a lot of wind at higher altitudes, which was something for the team to factor in as they completed their works nearly 120m above the ground.
Traditionally, the client that contracted JYC used lattice boom crawler cranes to complete this kind of work in other regions, but as John says: “big crawlers can be difficult and slow, pieces of equipment to move, that often end up holding more capacity than what is required for component changeouts”.
“Sometimes, a customer prefers the use of a lattice boom crawler crane in these scenarios because it provides them with a little bit more leeway in terms of capacity,” he says.
“Our case for winning the contract was different; we believe that contracts can be won and lost on the mobilisation strategy, and so we pitched a different case.”
The business case pitched to the wind farm operator was clear: instead of using a large crawler crane that would take longer to transport and require many more trucks, why not use two hydraulic cranes operating within their maximum capacity, providing a much more economical, time efficient, environmentally conscious lift?
The choice was clear for JYC on which machines were going to be selected from its diverse fleet; the company is in possession of two 800-tonne Liebherr LTM 1750-9.1 all terrain cranes and, thanks to its V2E boom extension system, the machines thrive on jobs that require high lifting capacity at substantial hook heights.
Needing to complete its repairs on the turbine in question at a height approaching 120m, JYC’s LTM1750 Liebherr cranes, with maximum hoist heights of 152m each, safely completed the three blade dual lifts while then allowing the lead crane to remove the heavier driveline components without changing position or reconfiguring the boom or fly.
“The reason why we chose this crane is because it’s optimal for this kind of travel,” says John. “If you combine the lifting power of the LTM1750-9.1 with roadability benefits, overall, it’s the best crane by far. Our LTM1750 crane is the perfect point of lifting power, versatility, and roadability.”
Road Access Challenges:
One of John’s biggest challenges and indeed favourite personal moments to come out of JYC’s recent refurbishment of two wind turbines in Central Victoria was obtaining access for two 800-tonne hydraulic cranes to complete a 1200km round trip with their booms still attached.
Travelling from its Campbellfield depot in Melbourne’s north, the road access team at JYC needed to be realistic about axle loads for the journey to the wind farm while still achieving an efficient mobilisation compliant with Victoria’s complex heavy vehicle road rules.
John relied on his past experience at CICA and alongside the Department of Transport to achieve a feat he says he’s “really quite proud of”: moving both cranes to the jobsite without needing to remove either boom.
This ‘European style’ scenario is unique to Victoria where this level of crane access is allowed to exist, and John pays tribute the progressiveness and pragmatism of the Victorian Department of Transport.
Citing the complexities of navigating the bureaucracy involved in moving the machines, John says the team at JYC needed to lobby with local governments to gain access to certain bridges so they could bypass other bridges on the main highways that they weren’t allowed to cross.
“Being able to be part of a lift involving in such a significant mobilisation strategy involving our two biggest cranes travelling at a heavy weight that we would not normally be able to do in the past is a logistical milestone for us,” he says.
“It helps us reduce time and operational costs because now we don’t need to spend time putting the boom back on the cranes.”
“Additionally, it helps the construction industry shift toward more leaner and efficient practices,” he continues.
“By being able to move the cranes with their booms on, we reduce our logistical/carbon footprint because now we don’t need a second crane in support, and we don’t need as many trucks and trailers carrying counterweight and equipment.”
Transporting the machines to the jobsite in an efficient manner is one thing; erecting the cranes at the wind farm is another.
JYC’s LTM1750-9.1 cranes possess a telescopic boom that extends out to 52m.
What it also features, however, is a lattice jib extension that can provide the crane with an additional 91m of boom.
For its job in removing and lifting the blades into position, and replacing the generator, JYC needed to configure its machines with the over 50m of boom extension to provide maximum reach to its 114m tall job.
To assemble the cranes, a 40-tonne Franna pick and carry crane was deployed to build and attach the crane’s boom extension and luffing fly.
There was a problem, however; the crane pad was, in a rough estimate from John, “75m by 45m and on the side of a steep hill” – a significant issue when both crane’s booms extended nearly 90m each.
“When they build these wind towers, they just typically put erect one big crane in the middle, and so the crane pads is are designed to accommodate just that,” says John.
“For repair and maintenance work, there are portable sheds and all sorts of equipment along with two big cranes (in this case) all on the crane pad at the same time. There is not a lot of room, so we played a Tetris-like game fitting the two LTM1750s on the crane pad with all the blades and components.”
After equipping the primary crane with 124 tonnes of counterweight and the secondary one with 94 tonnes, the team was ready to start their dual lift on the wind turbines.
A team of six people was constantly on site to complete the job: two operators, one in the tower, and three on the ground. Using rigging equipment supplied by the client – thanks to the fragile nature of the wind turbines themselves – the job also required multiple engineers working for JYC’s client watching both from the tower and from afar to help maintain the balance of the turbine as it was being lifted.
One of the complexities in the dual lift that John points out was navigating the small dimensions of the crane pad for the cranes to be able to operate in their working range. In their configurations, the machines needed to be operating at a minimum radius of around 30m. Without these inbuilt limitations, the crane could fall over backwards with no load on the hook.
“The whole point of a crane is usually to lift heavier items at a larger radius,” he says. “Our challenge here was not so much maximum radius but minimum radius due to the 56m and 59m fly jibs.
“At times we had a very narrow working range as moving out from our minimum radius meant capacity dropped off very quickly, pushing our lead crane well above 90 per cent capacity to complete the lift.”
Further difficulties arose with the very essence of a wind turbine blade; as a 60m long component designed to catch wind in a purposely selected windy area, a max wind speed of 30km an hour was something that needed to be factored in when removing and lifting the blades back into place.
“With a dual lift, you’ve got to derate the capacity of the cranes,” says John. “There’s a lot at stake lifting these blades back to their positions. Everything needed to be kept dead level, or else the blade may slip out at either end of the supplied rigging.”
To accommodate this, JYC sent one of its team members away to watch the lift from a vantage point to keep an eye on the horizontal alignment of the cranes, with a radio on standby to sound the alarm should anything look out of place.
“To ensure these were safe, efficient dual lifts, we needed every single member out there keeping an eye on things and making sure that everything was proceeding exactly as it was designed,” says John.
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And so, having successfully completed this project with 12 successful dual lifts and 12 single lifts, providing resource-saving solutions to a complex logistical problem, the team at JYC promptly demobilised the machines and sent them straight back to resume work in Melbourne.
The success JYC enjoyed on the project was the result of close collaboration with the client, communication among stakeholders in the mobilisation process, and the “professionalism” of the crane, the transport and the client’s MCE crews according to John.
“These factors were pivotal to ensuring that our methodology for this project came to life, which resulted in reduced overall costs by performing the dual lift with our two largest cranes,” says John. “Additionally, we were able to minimise truck movements and emissions with a lean logistical footprint, and collectively we demonstrated that it can all be done safely, compliantly, reliably and efficiently.”