Lift Planning Requires Strict Attention When Working On Wind Projects

Tue November 19, 2024
Lucy Perry – CEG CORRESPONDENT

Mobile cranes, especially crawlers and all-terrains, are critical components in wind turbine installation. When it comes to hoisting blades and tower sections into place, cranes provide the lifting capability contractors can't get with other machines. But there are basic ground rules contractors need to know in planning turbine transport, installation and maintenance.

Poor planning and the wrong team on a wind installation project can result in missed deadlines, unexpected costs or even damaged components and machines.

Lift planners need to plan for logistics, crane transport and, once on site, ground conditions. With vertical operations, wind conditions are a factor, as well.

Working From the Ground Up

Cranes at wind farms are larger, with longer crane booms that are often 300 or more feet in the air, said Hank Dutton of Travelers Insurance.

"Ground conditions are really critical," said Dutton, senior regional construction specialist of Travelers. "The ground needs to be level within the crane manufacturer's specifications."

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The surface also must be "strong enough to resist the forces imposed by the crane, which can be greater than the weight of the crane, plus what is being lifted."

Every lift should be considered a new lift — operators and crews need to resist complacency.

Uneven ground conditions, high winds and other factors can make wind farms especially risky for cranes, he said.

Besides lift planning and operations, wind farm developers and contractors should consider the unique risks of cranes in transit at their site, urged Dutton.

"From steep mountain-top sites in the northeast to soft ground conditions at farmland sites, crane operators face significant risks when walking cranes from pad to pad."

With a long history of advising crane company clients, Travelers offers tips on specifically for contractors working in the wind sector.

1. Make sure lift plans reflect wind farm risks.

Create a lift plan that reflects the conditions expected at the site and addresses the crane manufacturer's limitations and specifications.

"Each site pad has a different set of conditions that needs to be evaluated carefully," Dutton said. "Review every lift plan with crew members involved, including the crane calculations, ground condition requirements and the associated rigging drawing."

2. Ensure riggers are trained in specialized rigging.

Rigging-related accidents at wind farms have the potential to create significant damage and cause fatal injuries.

"These are high-risk operations," said Jay Hurin, a Travelers risk control construction specialist.

Specialized rigging designed to lift long, heavy turbine blades can require additional training. Therefore, it is important to ensure riggers have reviewed the rigging manufacturer's instructions as well as the rigging drawing as part of the lift plan.

Risks include falling objects and being crushed by heavy equipment. There's also the potential for costly damage to the crane and the turbine. And "if something goes wrong, these tend to be serious accidents," Hurin said.

3. Create a plan that addresses the hazards when moving the crane.

The crew involved in relocating a crane between wind turbine pads should follow the site plans, which have generally been developed by engineers.

These plans should address the crane manufacturer's specs as well as the ground conditions needed to support the crane for the entire travel route.

"Not only can injuries and damages be severe, but so too can delays in the project as turbine blades usually have long manufacturing lead-times," Dutton said.

4. Monitor weather conditions.

Extreme weather can be especially dangerous at a wind farm installation. Have weather monitoring equipment on site and weather procedures established.

5. Re-evaluate site conditions after severe weather events and site changes.

It's important to re-evaluate ground conditions after a severe weather event or other changes to site conditions.

"Analyze the conditions at the time that you're trying to walk the crane," Dutton said.

Another concern is traction of the crane when coarse aggregate is used for the roadway. The crane's tracks can start digging up the ground cover as it turns, and conditions can become dangerously unlevel.

"Operators need to understand the crane manufacturer's level requirements while walking cranes, including front-to-back and side-to-side," Dutton said.

6. Exercise caution when disassembling a crane.

The large-scale dimensions of wind farms can make distances between pads too great to travel fully erected cranes.

"There is an inherent risk in assembly and disassembly that people need to be aware of," Dutton said.

Employees can be injured or worse if pins are removed in the wrong order or counterweight is removed too soon.

Transporting a disassembled crane on a truck also requires performing due diligence.

That includes pulling appropriate permits, making sure the load is properly secured and ensuring that drivers are qualified. Contractors should check drivers' motor vehicle records and confirm that they are properly licensed.

7. Follow road plans for established sites.

When significant maintenance needs to be performed and cranes are brought back on site, it's important to first establish safe conditions. This can involve replacing access roads and installing crane pads to ensure that soil is stable for transporting and using cranes.

It's important to have a qualified professional design a road plan that addresses slope, firmness, compaction and levelness for the entire route

"Sometimes that means rebuilding access points across a large site," Dutton added.

8. Have a commitment to safety at all levels.

"There really needs to be support from management, including the site superintendent," said Dutton. "One bad decision … can lead to a costly accident."

Creating a culture of safety can help crane operators, spotters and other members of the team feel more empowered, he said.

That encourages employees to report potentially dangerous site conditions that might delay the day's activities and avert a potential disaster in the long run.

Strategizing for Efficient Maintenance

Gerrit van Doornik of Wind Solutions said two of the primary costs of crane operation, especially in wind farm work, are transportation and downtime.

Cranes require dismantling and transporting site to site, which can drive a single day's rental costs to $50,000 depending on how crane size fits the job.

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Van Doornick, president of the turbine parts and services company, told windpowerengineering.com that 20 or more truckloads may be required for transport.

"Each truck can move a load about 600 miles a day, or multiple loads over a shorter distance," he said. "If a crane needs to move 100 miles, it would likely need a truck to move two to three loads in a day."

He said that means mobilization costs can add up to almost 50 percent of overall crane cost, even for a single turbine repair. He advised that, on the turbine maintenance side, economies of scale and careful planning are the solution. If a turbine needs major maintenance every five years and the maintenance cycle lasts one week, a single crane could maintain 52 turbines per year.

Van Doornick believes that on a wind farm with many turbines located close together, a crane sourced full-time to that site would cut down on relocation costs.

"Onsite labor downtime can add up as well," he said. "Once the crane is delivered, it takes a few days to set it up, depending on crane type."

And when maintenance tasks are completed, it takes another couple days to dismantle and prepare for loading onto trucks to start the process again. Also, the crane team and turbine technician team work on different scopes. When the crane is being assembled, moved or disassembled, the tech team is idle.

This means more crane personnel are needed. Once the crane is ready to work, the technicians are working but fewer people are needed on the crane side.

"This leads to inefficiencies on both teams; up to 40 percent of labor costs can come from idle time," said van Doornick.

He added cross-training technicians to be proficient in both crane operation and wind turbine maintenance can be an effective way to reduce costs. This cross training also can improve the efficiency of the entire process by eliminating the need for separate technicians for each task.

"Companies can save significantly on recruiting and reduce the number of personnel on site," he said.

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Another plus? Cross-training can improve the overall efficiency of the maintenance process, said van Doornick.

"Having technicians familiar with both cranes and wind turbine communication and coordination can streamline the work and reduce downtime."

He added for the wind turbine owner, this makes the process far easier because a single contractor can complete each element of the turbine maintenance process.

"However … it requires time and resources to provide the necessary education and ensure that technicians are proficient in both areas," he cautioned.

Ultimately, cost savings and efficiency make cross-training crane teams a potentially worthwhile investment, said van Doornick. CQ