Wind accounted for about 50 percent of renewables-based power generation in the past few years, Qian said, citing a Mckinsey Energy Insights’ Global Energy Perspective report released in January this year. All renewable sources currently account for a combined quarter of total power generation capacity, and that number is expected to rise to 50 percent by 2035 and to almost 75 percent by mid-century.

Gear wind turbines will be the leading technology and will [account for] about 20 percent to 30 percent of total power generation, Qian said at the Asian Industrial Lubricants Conference held here, jointly organized by ICIS and the European Lubricating Grease Institute. In the future, gearboxes will also become bigger as the wind turbine capacity increases.

Gear oil is projected to be the fastest growing lubricant segment, with a compound annual growth rate of 8.1 percent from 2018 to 2026, a jump from $122.7 million in 2018 to $226.1 million in 2026, according to Global Lubricants for Wind Turbine Market, a report by New York City-based market research firm, Reports and Data. Demand for gear oil lubricants is expected to witness an upward trend due to the increase in contact pressures and expected increase in oil life span, Qian said. The gearbox is considered to be the critical component in terms of downtime and failure rates. Almost 70 percent of gearbox failures are caused by lubricant degradation, which reduces the life span of wind turbine operation, according to the report by Reports and Data.

A gearbox is placed on top of the wind turbine tower, and when the wind blades spin, the shaft connected to the gearbox increases the number of rotations to the generator for the conversion into electricity. The gearbox can convert the turning speed of the wind turbine blades from 20 rotations per minute to 1,800 rpm.

Consultancy Kline & Co. said in a November 2016 webinar that in 2015 about 35,000 to 40,000 metric tons of various lubricants were used in wind turbines and that China accounted for 33 percent of wind energy installed capacity, with more than 140 gigawatts of capacity. Gear oils accounted for 70 percent of that tonnage, and high-viscosity PAO was used to make about 65 percent of the gear lubricants. Kline forecasted that in 2020, wind turbine lubricant demand would reach somewhere between 51,000 and 65,000 tons, requiring about 23,200 to 42,200 tons of high-viscosity PAO.

Typical challenges of wind turbine gearbox lubrication include susceptibility to micro-pitting and wear, demand for extended oil drain intervals of up to seven years and the requirement for stable functioning under a wide range of temperatures.