Lifetime extension

Turbines are certified to a design life, conventionally twenty years, based on assumed load conditions for their design class. That assumption is generic. A machine that spent twenty years in gentler conditions than its class implies may have consumed far less of its structural life than the calendar suggests, and lifetime extension is the process of establishing that with evidence.

The assessment has two halves. An analytical part re-runs the fatigue calculation using the site's measured wind and turbulence intensity rather than the design assumption, and an inspection part examines the structures and components for actual damage. Where the operating record supports it, extensions of five to ten years are commonly granted.

The value is unusually high because the alternative is expensive. Extending an existing asset requires no new interconnection, no new permits in most jurisdictions, and no new civil works, so the incremental annual energy production comes at a fraction of the cost of new capacity. The competing option, repowering, buys more output but is a capital project.

What makes or breaks the case is the quality of the operating record. An assessment built on a complete, well-attributed history of what each machine actually experienced is far stronger than one built on assumptions, which is why the value of a clean SCADA archive tends to be realized at exactly this moment in an asset's life.