As turbines emerge from their warranty phase, wind farm operators face the stark reality that operation and maintenance costs will embark on a steep, upward trajectory, before leveling off over the next five years. What strategies can be deployed to mitigate these costs?

By Rikki Stancich in Paris

Currently, roughly 79 percent of operational turbines are still under warranty. For the 21 percent of operators on the other side of the comfort zone, an incisive O&M strategy could be the deciding factor between success and failure.

According to new research, operating and maintenance costs could be up to three-times higher than originally projected, particularly in the case of the multi-MW class of turbines coming online.

These higher-than-anticipated costs are the result of several factors. Chief among these is that the recent wind energy boom stretched the capacity of the existing supply chain. With manufacturers forced to rely on new - and often inexperienced - component suppliers, quality suffered heavily.

In addition, unexpected stresses placed upon today’s multi-MW machines have led to failures in gearboxes, generators, and blades. Consequently, components such as gearboxes, initially designed with a 20-year lifespan, are failing prematurely - in as few as 6-8 years.

“The increasing size of rotors and towers is placing unforeseen stresses on equipment not anticipated by existing design standards,” explains Peter Asmus, president of Pathfinder Communications and lead author of the latest Wind Energy Operations & Maintenance report.

According to the report, these problems may have peaked insofar as manufacturers have re-designed components and now rely more on in-house components rather than “off-the-shelf” components.

Another key factor resulting in early turbine failure is sub-optimal turbine positioning. Often, in order to maximize power production, multi-MW machines have been clustered in too-close proximity.

Positioning the turbines too close together creates tip turbulence, which magnifies loads on down-wind turbines. According to the report, the end result of this interference is increased wear-and-tear on the rotating parts of a wind turbine, boosting O&M costs and exposure.

Supply chain uncertainty

But component failure is only half the story. The real costs kick in when operators need to source and install replacement components.

Take gearboxes for example, which currently account for a large majority of turbine failures. The cost of component replacement, crane hire, post-installation testing and operational losses, can quickly add up to around US$500,000 per turbine.

To mitigate these costs, Asmus stresses that a preventative maintenance regime is crucial for curbing O&M costs. He points out that in this area, European operators have an advantage over their U.S. counterparts.

Europe’s premium power prices (achieved via feed-in tariffs) provide operators with a margin to invest in costly condition monitoring and performance systems, such as vibration, thermal and oil and debris sensors.  

In addition, a broader O&M service experience pool and the proximity of wind farms to O&M support infrastructure in Europe has enabled European operators to deploy preventative maintenance strategies. Subsequently, European operators face lower overall lower maintenance costs than U.S. operators.

U.S. operators are further penalized by the fact that currently, many components must be shipped from Europe, creating costly delays in repairs. While the U.S. government recently introduced measures to stimulate domestic supply, such as the Manufacturing Tax Credit, suppliers complain that several factors are creating barriers to entry.

A lack of standardization means that new components suppliers trying to break into the market are met with distrust. Unless standards, processes and procedures are introduced, it is unlikely that this problem will be resolved, suggests the report.

With the imminent emergence of many turbines from the warranty phase, many suppliers are viewing the aftermarket as potentially lucrative. As such, establishing industry standards and benchmarks would result in a more responsive supply chain.

O&M data elusive

On the flip side, operators – particularly those in the US – should be investing more in preventative maintenance strategies. But when it comes to forward planning, operators are facing a major hurdle in terms of a lack of relevant data.

Given the higher-than-expected failure rate of many turbine components, original equipment manufacturers are holding component failure data close to their chests to curb the risk of litigation and a negative public backlash.

And with the majority of turbines still under warranty, many operators simply do not have access to their own data sets. 

Meanwhile, publicly available data sets are in short supply and where they do exist, have often proven to be a poor fit, given that wind energy projects vary widely depending on terrain and wind regimes.

“This is an industry in transition, operating within an incredible vacuum of knowledge about O&M costs,” says Asmus.

Despite the problems, the report authors note that the problems facing the wind industry are typical of all industries as they scale up rapidly.

“Even with the unexpected increases in O&M costs, most projects in Europe still pencil out,” he adds.

Initiatives are currently underway in the US and Europe to ensure that more robust data is available in the future. In the US, the National Electric Reliability Corporation (NERC) launched a voluntary data collection programme on January 1, 2010 known as 'GADS'.

The GADS programme will likely evolve into a mandatory program in coming years, but for the time being, many operators are restricted to using limited, in-house data sets.

Despite looming O&M issues the wind industry remains optimistic about the future of wind technology, according to the report. Asmus suggests that the key lies in preemptive maintenance and the introduction of industry standards.

“The industry needs to shift from reactive to preventative maintenance and bring its supply chain up to a higher standard,” he concludes.

To respond to this article, please write the editor:

Rikki Stancich: rstancich@gmail.com

For further information regarding the report cited in this article, please click here, or visit the reports website at: www.windenergyupdate.com/reports.