For Tim Matthews, it would seem that “good enough” is never good enough.
The maintenance group site supervisor for Danish wind turbine manufacturer Vestas Wind Systems is continually looking for more efficiency in turbine maintenance and repair.
While recently retrofitting 50 Upper Michigan towers with lightning-deterrent blade tips, Vestas crews used four new self-propelled Genie SX-180 boom lifts. Offering 180 ft. of vertical reach, the new telescopic boom lift is the largest unit Genie offers.
After a cold, wet spring had hindered production, the four SX-180 lifts played a key role in helping Matthews' crews get back on track and complete the project a bit ahead of schedule.
Huge presence
“As a company, we’re among the leading wind turbine manufacturers in North America in terms of installed capacity,” said Matthews. “Our company is based in Denmark, but here in the U.S. we have sales offices in Portland, Ore., and manufacturing facilities at several locations in Colorado. Part of an after-sale service we offer is a maintenance contract with the companies that purchase our turbines. That was the case with Exelon Corp. (Chicago, Ill.) which owns and operates the wind farm called Michigan Wind 2 in the part of the state we call ‘the thumb.’”
The Michigan Wind 2 contract called for Vestas to install lightning-deterrent copper tips on the blades of each of the 50 turbines operating at the 90-MW capacity site. Even at their lowest, the turbine tips are more than 155 ft. off the ground, so access to the work area is, at best, challenging. Though they’d done this type of work countless times in the past, when considering the pending work, Matthews felt it was time to look into a better means for accessing the blade tips.
Newer, bigger, better
Matthews’ motivation to seek an alternative was partially based on information he had been receiving from Chad House, sales rep from the Midland branch of Titan Equipment. Ongoing discussions between the two had been centering on the new Genie SX-180 boom, which was just about ready to ship when the contract at Michigan Wind 2 was finalized.
“The timing couldn’t have been better for us,” says Matthews. “We had already been looking into using a Genie Super Boom on a previous project, but things didn’t quite pan out. The fact that these were coming available just as we were starting up was a good sign. Vestas is constantly looking for more efficient and cost-effective ways to do the job out here and these lifts, by nature of their much shorter setup time, looked to be a great solution for us.”
Matthews particularly liked the fact that the new booms offered 180 ft. of reach, about 25 ft. more than needed to do the retrofits.
“It’s nice to have that additional reach in reserve,” he says. “It allows us room to maneuver the boom into the best possible position, rather than being constrained by a boom whose reach has been maxed out." Matthews added that the extra 25 ft. of reach gave Vestas additional opportunities, like looking further up each blade for lightning damage or leading-edge erosion.
Safety first
While the height may seem daunting to the untrained, Vestas’ procedure was fairly simple. First, workers used controllers in the tower to move the rotor until the target blade pointed downward. They then set a service brake to lock it in place. Locking pins ensured that the blade and rotor stayed still.
“There is a pretty intense lock-out procedure in place anytime we are accessing these blades,” says Matthews. “Once we have it in position and secured, though, we simply boom up to the blade, remove the existing lightning receptor, and, using a combination of bolts and an adhesive, affix the new copper tip to the blade."
The biggest challenge thus far has been dealing with weather. Matthews said that although the adhesive that secures the new tips is extremely sensitive to temperature and humidity, his crew has managed to keep production up.
SX-180 features that proved particularly beneficial in the turbine project included the 8’ X 3’ work platform, which was ideal for two men and the retrofitting equipment, a chassis width that expands from 8’2” for shipping to 16’6” for working stability, and a 10-ft. jib that rotates 60° horizontally and 135° vertically.
“My crews report that having that kind of movement on the jib has been a real asset on this project,” said Matthews. “They’ve been able to access specific work areas much easier than in the past. As a result, production rates have been very favorable for us: depending on weather, we were generally completing three blades in two days.”
Respect for the dealer
Matthews says they’ve tapped alternative methods for turbine maintenance and repair in the past, but have found the Genie SX-180 booms to be ideal from both a performance and operational cost standpoint.
“We’ve used a couple different options, including one which involves a suspended platform,” he said. “That works but, because of the rigging involved, can be a four- or five-man operation, versus only two or three with the lifts."
Matthews said he's also subcontracted to companies that provide truck-mounted aerial lifts. "While those are effective, they come with their own set of challenges such as scheduling and equipment optimization. When we contract to a company like that, we commit to a pre-set time frame and if, for some reason, there is downtime in the project, we are still paying for their time while the machines sit idle. And if they have other commitments after our contract is up, they are gone and production is halted until they are available again — and they are often solidly booked. It can be a headache.”
By comparison, working through Titan Equipment, Matthews and his 24-person crew rents the self-propelled boom lifts, gets fully trained on operation and safety, and begins work. As a result, Matthews reports seeing a reduction in overhead and standby costs.
According to Matthews, the relationship with Titan has been solid.
“Titan has been just outstanding before and throughout this project,” he said. Even though the Vestas crew has had to work some weekends to make up for weather delays, "Titan has always been there to accommodate our needs."
Vestas’ crews at Michigan Wind 2 kicked the retrofit project off in early May and, despite an abnormally cold spring and rising humidities throughout summer, completed all 50 towers by mid-July.
“There’s no doubt having the luxury of those lifts helped us in that regard. On larger projects like this, hands-down I’d say that’s the way to go.”
Lift & Access is part of the Catalyst Communications Network publication family.
