Yet, while CMS is well established in other North American industries and in Europe where insurance firms practically mandate it before offering a policy to a wind farm, estimates suggest that only 10% of the US wind fleet uses CMS to anticipate failures and schedule repairs.
As turbines get bigger, more costly and more expensive to repair, the debate continues with no consensus in sight: Is paying $20,000 per turbine for CMS a no-brainer investment? Or is it better to use common sense and an owner's manual throughout a turbine's 20-year life?
CMS applied to wind turbines usually takes one of two forms. Vibration monitoring is more costly and more widely used. Sensors are attached to gearboxes, generators and drive trains to provide real-time data streams that are transmitted to operators who monitor the results on a computer for changes that highlight a potential problem.
Automated oil-particulate systems count metal pieces floating in lubricating fluid, either displayed as real-time data or stored for later examination. Increasing rates of gear-tooth or bearing particulate indicate trouble.
Beyond those mainstay methods, acoustic monitorsare newcomers to a CMS niche market where dozens of competitors have popped up in recent years. Borescopes can take photos inside the gearbox, much like a medical procedure, but are not considered CMS because a complete scan can take eight hours and is largely inefficient unless specific problem areas are already known.
Clipper, Siemens and Gamesa are among the turbine manufacturers that provide CMS as standard equipment in the US. Others offer it as a pricey factory add-on and many don't offer it at all. Insiders say that few firms welcome the intense scrutiny of CMS, preferring that the data remains proprietary. Some dismiss all such technology as unproven.
So, many companies simply send a technician up-tower to collect gearbox oil in a vial and send the sample off to a lab for quarterly particulate counts - at $30 per turbine. A few others stick to the age-old method of rolling down their pickup-truck windows, driving slowly through the wind farm and listening. Those numbers are dwindling.