The challenge, however, is how to achieve that one percent improvement in the face of operations and maintenance (O&M) costs that are double or even triple initial projections.
O&M costs under-estimated
On the basis of an exhaustive industry survey, the latest report finds that wind farm return on investment is around -21 percent. This underperformance is attributable to over-estimation of power production and underestimation of O&M costs say the report’s authors.
In the early days, the industry had costed out O&M at roughly 0.5c/kw over a turbine’s 20-year life. But as newer models and their respective components continued to flood the market, this has turned out to be far from the reality.
The report highlights that wind O&M costs can now be expected to increase on average 253 percent over the 20-year life of the various wind machines.
“Given that every wind turbine comprises an average of 8000 components, it is not surprising that higher-than-expected rates of component failure continue to plague the industry,” say the report’s authors.
Understanding the root cause
The constantly evolving wind turbines market means that new components must continually be demonstrated, with little assurance of their availability five years down the track in the event of component failure.
Of even greater concern is that, if not properly addressed early on, component failures can persist through new product generations. It is therefore vital, despite pressure from competitors to continuously push the boundaries on nameplate capacities, that both the onshore and offshore industries adopt a backwards compatibility approach when evolving each model.
A thorough understanding of failure trends can also provide a basis for the best O&M practices for a given system, say the reports authors.
Sketching a component failure timeline, the authors characterise earliest wind turbine designs (1987-91) by their gearbox failures, while wind turbines built between 1994-99 are characterized by electronic power failures.
Wind turbines manufactured between 2000-2004, again exhibit problems with generators and gearboxes. More recent models are plagued with issues linked to retrofits.
But there is a silver lining. Some component suppliers to the OEM wind turbine market view the aftermarket as a new, long-term opportunity.
“Advances in turbine design may make certain parts obsolete, but with a typical projected turbine life of 20 years or more, the aftermarket will provide ongoing spares demand for these suppliers for some time to come”, says the report.
The report also notes that in the long-run, as the wind industry matures and begins to validate the success of condition and performance monitoring systems, as direct drive wind turbines replace gear-box driven turbines, and as the industry begins to collaborate on O&M, reductions in long-term O&M costs are the most likely scenario.