Delivering the proof: A deep dive into blade bearing greases

By Douglas Tshudy, Global Wind Sector Marketing Manager, Lubricant Solutions, Shell

As wind farms expand into increasingly diverse and harsh locations—from the freezing conditions of high-altitude mountain ranges to the blistering heat found in arid desert landscapes—wind energy teams navigate shifting and complex challenges, particularly equipment stress and accelerated wear. Wind farm teams must strategically preserve the equipment’s resilience and maximize efficiency.

Challenges that greases need to overcome

Selecting the right bearing grease can be a consequential choice to help prevent unplanned downtime and expensive repairs. Grease ensures smooth blade movements, thus strongly influencing operational performance and directly impacting reliability over time. Without optimal lubrication, key interfaces or mechanical systems can overheat and ultimately fail. However, high-performing lubricants reduce that friction and wear and protect the blade, yaw and pitch bearings from damage caused by:

• Water contamination (ingress) causing corrosion
• High impact load due to unpredictable weather conditions

Severe wear due to insufficient (re)lubrication Water contamination is a challenge for operators to ensure consistent performance. The risk of a grease losing its integrity increases as turbines are exposed to rain, high humidity, and condensation due to varying temperature during operation and standstill. To address this, lubricant manufacturers incorporate moisture-repelling additives into their advanced formulations to form a shield against water ingress. Interestingly, third-party evaluations by Fraunhofer IWES in Hamburg, Germany, found that Shell Rhodina BBZ maintained functionality and minimized raceway damage with up to 10% water exposure—significantly outperforming other greases that failed at just 3% water ingress.[1] This performance advantage makes this advanced grease an option for wind farm teams in harsh environments where moisture resistance is critical for sustained equipment life.

Additionally, this research confirmed that Shell Rhodina BBZ outperforms commercially available formulations in slow, oscillating wind turbine pitch bearings. Water-repellent greases often fail in these conditions due to insufficient film formation capabilities, leading to increased fretting wear and eventual lubrication/component breakdown.

With installations in harsh, frigid locations, energy teams must regulate temperature swings to help maintain grease consistency. These conditions cause conventional greases to lose effectiveness and thicken excessively; however, it is crucial that lubrication remains fluid for reliability in freezing temperatures. Shell Gadus S5 V110KP 1 maintained a consistent functional range from -40°C to +120°C in third-party evaluations.[2] It showed minimal wear in freezing conditions, making it well-suited for installations in arctic and marine environments. This specialized lubricant is formulated with synthetic base oils, advanced additives, and thickeners for low-temperature fluidity to ensure stability and prevent hardening, thus ensuring sufficient lubrication in any conditions. Shell Gadus S5 V110KP 1 minimizes wear across a wide temperature range, including low temperatures, outperforming higher-viscosity alternatives.

Since wind turbines operate differently than conventional rotating machinery, rather than spin (unidirectionally) continuously, wind blade bearings move in slow, oscillating motions, around 0.5 Hz, with one movement every two seconds to adjust the pitch angle of the blades. This increases stress on bearings in unique patterns, requiring grease to adapt to this to lubricate the bearings without breaking down over time. In the Fraunhofer IWES study1, both Shell greases performed well in variable amplitude conditions, mimicking operational conditions of real blade bearing operations as they are engineered to handle real-world variable loads.

Next Generation of High-Performing Lubricants

Ongoing advancements in lubrication technology support next-generation wind systems, now designed with larger rotor spans, taller towers, and heavier mechanical loads. Many lubricants today were initially formulated for other industries rather than being designed specifically for wind turbines. To keep pace, Shell tailored new formulations for wind turbine applications to ensure that turbines remain reliable over their multi-decade lifespans.

With up 800 GW in capacity projected to be installed by 2028 4, wind farm teams must implement forward-thinking strategies to sustain equipment performance, as enduring efficiency will be crucial for future success. Choosing proven, advanced lubricants is an investment in keeping wind systems running smoothly and sustainably with:

1. Extended maintenance intervals
2. Reduced downtime
3. Lowered overall service costs
4. Enhanced component durability
5. Minimized lifecycle expenses

As wind farms expand into more complex environments, selecting validated, field-tested solutions is key to maintaining sustained efficiency.

To learn more about Shell Rhodina BBZ & Gadus S5 V110KP 1 and Shell’s complete lubricant service offering for wind turbines, visit  https://www.shell.us/wind or contact your Shell representative.

Shell Cautionary note: https://www.shell.com/investors/disclaimer-and-cautionary-note.html

1 Fraunhofer IWES Study: Short-Term Influence of Water Ingress on Wear in Pitch Bearings of Wind Turbines
2 Low Temperature Study: Wind turbine lubrication: Low temperature fretting wear behaviour of four commercial greases
3 ProMarket Reports: Wind Turbine Lubricants Strategic Roadmap: Analysis and Forecasts 2025-2033
4 Global Wind Energy Council: Global Wind Report

Sponsored content by Shell Lubricants

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