This is an excerpt from the Second Quarter 2011 edition of the Wind Program R&D Newsletter.

Wind turbine gearbox failures have been one of the most costly issues that faced the wind energy industry. Unknown, unsteady operating conditions and debris entering the system accelerate failure of components like gears and bearings. Repairs and replacements are costly and contribute to significant downtime. Researchers at DOE's Argonne National Laboratory (ANL) teamed up with industry and university partners to find a way to lessen drivetrain component failures by developing novel materials and lubricants tailored for the harsh operating conditions of wind turbines. The ANL team took an approach that combined surface engineering and lubrication. They started with a revolutionary surface treatment, using ultra-fast boriding for the material side. Then they applied a novel nano-lubricant designed to eliminate much of the materials and lubrication-related problems, such as micropitting of gears and bearings, fatigue cracking, and scuffing, as well as hydrogen embrittlement and tribocorrosion.

The approach proved successful as the team's application of the ultra-fast boriding method to the gear steel material achieved a thick and uniform hard layer. The boride layer demonstrated an enhanced wear resistance by an order of magnitude greater than standard carburized surface treatments. They also confirmed that the nano-colloidal lubricant additives physically and chemically interact with the surface to form a durable protective layer on contacting surfaces. ANL used a lab-scale test rig as the means to simulate gear tooth/bearing contact and induce micropitting and surface fatigue failures, allowing systematic evaluation of lubricants and surface treatments.

The project already has shown significant advancements in the development of novel surface treatments and nanolubricant technology. Such gains will lead to cost-effective methods for mitigating wind turbine gearbox failures and therefore reduce the cost of wind energy. ANL plans to continue and expand this initiative, working with industry and academic partners to further optimize the solutions for the severe operating conditions endured by wind turbine drivetrains. Eventually, these novel treatments and advanced lubricants will be validated and field tested in full-scale gearboxes in coordination with existing and new project partners and then implemented in wind turbines.

Argonne National Laboratory in Argonne, Illinois, is also developing improved methodologies for wind power forecasting and is working to increase the deployment of advanced wind forecasting techniques that will optimize overall grid reliability and systems operations. Work at ANL is also underway to assess and mitigate environmental impacts of wind power plants.