What's the secret of cost-effective wind turbine maintenance? Mechanical expertise is crucial, of course, but the view of one of the world's largest electrical components companies is that the business of keeping turbines running smoothly is less about somehow hiring inexpensive teams of rocket scientists and more about the humdrum task of getting competent technicians to wind sites without breaking the bank.
It is arguable that never before has such a volume of aerospace-grade machinery been spinning so far away from the industry and population centres that need to serve it. This is particularly the case in the US, where most wind farms sprout up across the rural windy plains states that stretch over 2500 kilometres from Texas to North Dakota. The multi-million-dollar turbines dotting the countryside need regular servicing to ensure smooth, efficient operation and predictive analysis and maintenance to avoid costly downtimes.
Some predictive maintenance can be done remotely with sophisticated technology. But most turbine maintenance still requires workers on the scene. Getting the manpower and expertise to geographically diverse and distant wind farms is a major cost of the operations and maintenance business, says Glenn Hanley, a senior manager for ABB's power systems division. The Switzerland-based company's pedigree in the traditional electric industry is known to most in the power businesses. One of its recent accomplishments was building a 1000 kV transmission line, located in China. The company's name is also stamped on many important wind farm parts such as generators, transformers, switchgear to the electrical collector stations and substations at the ground level. For wind, ABB has long provided service for its parts in the field. Hanley says that the range of wind service is so broad it is easier and quicker to describe what ABB does not do: blade work, project construction and day-to-day operation of wind turbines.
In the past six months, ABB has restructured and expanded its US wind service division in order to tackle the logistical challenge inherent in operations and maintenance. Hanley says: "Wind turbines are so diverse across the country that mobilisation costs that are minimal on urban substation work become quite a big portion of the cost to the vendor for wind service. Once the guys get there, it's the same old thing, the same diagnostic tools, the same hand tools. The difference is in actually getting them there."
ABB had traditionally operated two divisions involved in service for wind farms. The first is a team for drives and turbines, which largely covered up-tower equipment such as generators and transformers and, in many cases, the meshing of the entire drivetrain. While ABB does not manufacture gearboxes, it marries the drivetrain components together as a system and analyses current outputs throughout the system. A separate medium-voltage service team focused on electricity collection, distribution and substation systems. But the two divisions were not the most efficient for distant wind stations. "We were spending too much money," says Hanley.
Seeing the opportunity for cost savings, ABB recently formed a central wind plant service division combining the drives and turbines team with the ground-based medium-voltage team and expanded it with new members of staff who are spread out across the US. "When we send a team out there for service they will be capable of assessing all other things at the site," says Hanley. "So if you're going to pay mobilisation for us anyway, let's take advantage of that large cost and get as much done with the same team as we can."
It may mean another day on site, but the mobilisation costs are so large that the extra service time is minimal compared to the cost of getting technicians onsite in the first place. "To handle the task on a national level over the past year, three hundred new staff were recruited through arrangements with approved service providers throughout the US," says Hanley. "These are independent maintenance and testing shops already set up throughout the US. Ramping up staff with in-house resources would have been impossible for such a task." The new arrangment should result in response times closer to a few hours, on average, instead of the 16-, 18-, even 24-hour drives that have been necessary in the past. Service teams will be available for sudden emergencies but in most cases will be deployed for once-yearly visits to wind stations. The visits can vary from days to weeks in length, depending on the amount of work that is required.
Hanley admits ABB is not always the first name mentioned alongside wind plant operations and maintenance in the US. The big O&M providers in the US are Enxco, which is owned by France's EDF Group, EMS and a number of smaller independent service providers. NextEra Energy, formerly FPL Energy, also operates a very large in-house service team for its big fleet of turbines across the US.
"What makes us different is that we supply most of the equipment," says Hanley. "We have the expertise because we designed it, we built it, and we originally tested and commissioned it." Since ABB is a dominant player in the design and engineering of the original systems, they are therefore the best at servicing it, argues Hanley. "We carry the reputation because that transformer or generator actually says ABB on it." Costs for service are charged by the hour, with some variation for the type and extent of work being done. A typical yearly electrical systems check-up gives some sense of the costs, at least from the base of the towers to power grid. Hanley assumes a typical wind project in the US going up today would typically comprise 50 turbines, with the units ranging between 1.5 and 2.5 MW. According to analysis from the Lawrence Berkeley National Laboratory, the average size of wind turbines installed in the United States in 2008 was around 1.67 MW, up slightly from 1.65 MW in 2007.
For a team to test all the electrical systems and output would cost a typical 50 turbine wind plant around US$30,000 yearly, according to some estimates. That does not include the additional costs incurred should up-tower inspections be required. Overall operations and maintenance cost in the wind business is a murky topic with most operators hesitant to give figures, says Hanley. "We're not there yet," he says. "That's info that we could ask, but they would never tell us. We're going to have to get that answer through the back door."