GE sued by AEP over multiple turbine defects at giant US wind farms
Developer claims GE is wriggling out out of warranty when it too has launched legal claim against bearing manufacturer
GE is facing a multi-million dollar lawsuit over what are said to be serial defects and refusal to accept warranty claims on hundreds of wind turbines supplied for the 999MW Traverse Wind Farm and two other projects in the US state of Oklahoma.
American Electric Power (AEP) filed a lawsuit with the New York Supreme Court last Friday on the grounds that wind turbines had exhibited "material defects on major components and experienced several complete failures” within two or three years of commercial operation.
The complainant said a significant portion of the turbines have already been rendered inoperable, requiring repair.
But a much larger portion of turbines were described as exhibiting one or more material defects that were "reasonably expected to result in failures within their useful service life that will require expensive repairs".
The complaint was lodged against GE Renewables North America. The wind business of GE is now under the umbrella of GE Vernova since the latter was spun-off earlier this year.
The alleged defects affected a range of turbine components, but main bearings were at the heart of the complaint.
The main bearings hold the drive shafts connecting the rotors to the turbine generators and allow the drive shafts to rotate freely to generate electric power.
In its filing, AEP said some main bearings have failed completely on all three projects, requiring immediate repair and replacement.
The company said many more turbines are showing significant signs that premature bearing failure is imminent, describing defects such as "spalling, cracking and etching".
"AEP had no choice but to de-rate certain generators in order to continue operation because complete failures are occurring so quickly that AEP is struggling to keep up with replacements" the filing stated.
At one point, only 70% of the wind turbine generators on one project were in operation or were operating properly due to these problems, AEP said.
According to the court documents, GE’s own root cause analysis identified as one of the apparent causes of the main bearing defects to be "application of a diamond-like carbon (DLC) coating to the main bearing rollers".
A lack of a electrical grounding system for the affected components was also identified as a contributing cause, at least in part, of the premature cracking, spalling, etching, and breaking of the bearings.
Turbines in the spotlight
The wind turbines at the centre of the claim were originally sold under three contracts to Invenergy, before the Chicago-based power generation developer sold the relevant assets to AEP.
All three contracts were for wind farms in Oklahoma. One of these — which provided for the supply of 275 2.8MW machines — was for the 999MW Traverse wind farm.
The Traverse wind farm has a total of 356 wind turbines and was described by US Energy Information Administration (EIA) as the largest wind farm built in a single phase in the whole of North America when it came online in April 2022.
Together with the nearby Sundance (199MW) and Maverick (288MW) wind farms, it forms the 1.48GW North Central Energy Facilities project.
The court document stated that GE's own mechanical reports stated that the life of the WTG main bearings is supposed to be as much as 30 years.
Despite the root cause analysis, the documents assert that GE has so far rejected AEP’s warranty claims repair or replacement of all defective wind turbine generators on the basis the defects did not result in complete failure during the relevant period.
AEP said it has already incurred millions of dollars in costs and damages due to the need to repair or replace wind turbine generators in order to meet the energy production requirements of its customers, with more to come.
GE 'aware of problem'
AEP alleged that GE was aware that the DLC-coated bearings used on the turbines in question carried a high risk of failure and should not, therefore, be able to avoid warranty obligations for failures that are imminent or reasonably expected to occur.
To support this allegation, the complaint cross-filed 2023 New York State court litigation between GE and Swedish bearings manufacturer SKF Group.
GE had alleged that SKF-manufactured bearings had begun to repeatedly fail at a point identified as April 2021, and submitted estimated cost and repair damages exceeding $386m as a result.
"GE... has even sued SKF because it knows, at the very least, that all DLC-coated main bearings will fail prematurely," AEP's complaint stated.
AEP noted that GE based its own case against SKF "on the expectation that the bearings would last at least 20 years, and was seeking to recover damages and a declaratory judgment for the costs to repair or replace main bearings that will foreseeably fail, even if they have not already failed".
"In spite of overwhelming evidence and documentation that the wind turbine generators for all projects were defectively designed and have material defects to several critical components, GE has failed and refused to repair and replace the main bearings and other components for all wind turbine generators, in violation of the terms of the Contracts for all three projects, " the court filing stated.
Blade blame
Other alleged defects listed in the AEP complaint included cracks in the outer rings of the pitch bearings that connect wind blades to the rotor hub, downwind migration of the torque pins that connect the gearbox to the nacelle frame and blade issues including cracks, vibration and delamination.
In May 2023, an outright blade breakage was reported on the Sundance project and AEP alleged that GE was also at fault in failing to prevent this incident from occurring.
According to the filing, GE’s contracted drone-based inspection had identified a severe blade crack on the affected WTG days before the breakage, but did not communicate that information,
According to the filing to the New York court, "GE failed to notify AEP of the severe defect and extreme safety hazard, despite having knowledge of the same. Lacking knowledge of the results of this particular inspection, AEP returned the tower to service."
It continued: "AEP’s own investigation of the blade liberation event revealed that tower WTG-020 would have been shut down had AEP known of the defects and blade cracks identified by GE’s drone-based inspection vendor."
The breakage occurred 8-9 metres from the blade root.
Future liability?
In addition to its claims for monetary damages, AEP is seeking a declaratory judgment that GE is liable for expected future failures of wind turbines.
Phillip Totaro, founder and CEO of renewable energy intelligence firm IntelStor, who highlighted the case, commented in an online post: “This litigation could have huge implications on the long term service agreements (LTSAs) which have been signed by wind energy asset owners and other OEMs who are also falling behind on their contractual obligations on LTSAs.”
“We are disappointed that AEP has chosen to file this litigation. We care deeply about our customers and their success and will continue to work closely with AEP. We are currently reviewing the litigation and do not have any further comment at this time,” a spokesperson said.
AEP and SKF have been contacted with requests for comment.