Gearbox failures in wind turbines

Traditionally over 80% of the world’s wind turbines have used a 3-stage gearbox as a core drive-train component. As turbines have grown in size, however, the gearbox has emerged as a critical failure point, requiring replacement 2 to 3 times over the 20-year life of the turbine.

This creates a serious issue for wind farm owners. The combination of high operating costs and extended downtime plus a $400k to $500k replacement price for the gearbox can cripple the economics of a wind farm.

As a result, demand for direct-drive wind turbines is growing rapidly. However, there remains a large number of existing geared turbines for which a full replacement doesn’t make economic sense. There is currently no way for owners of geared turbine models to solve their in-field problems and no way to upgrade their existing design to direct-drive.

In China, the world’s largest wind market, this problem is magnified because their gearboxes are failing even more quickly and none of China’s leading generator makers has a direct-drive solution to sell.

This massive problem could take turbine manufacturers in China years to correct because developing and protecting a new direct-drive generator design is a slow and costly process, made all the more difficult by a crowded and complex patent landscape.

Loss of efficiency from high-variability energy sources

A traditional electric generator is very efficient when the energy source spins its shaft at a pre-specified speed and torque, but its efficiency drops when the energy source varies up and down (as, for example, wind does). In an effort to compensate, engineers place machinery between the energy source and the generator in an attempt to buffer these swings. This approach is complex and involves even more gearbox issues.

Exro’s patented Variable Input Electrical Generator (VIEG) takes a completely unique approach. The VIEG has been designed from the ground up to embrace the variability of natural energy sources, and to operate at peak efficiency across a wide band. Instead of relying on heavy equipment (more gearboxes) to accommodate variability, Exro’s technology uses multiple induction units paired with an intelligent controller.

The result is a generator that:

• Reduces capital costs for wind farm owners
• Offers double digit increases in turbine output
• Wastes less energy

Learn more about Exro’s patented technology, the Variable Input Electrical Generator (VIEG), and the benefits our technology provides.