Smarter blade repair: turning 1,123 blade findings into two repair campaigns

About them

The customer runs 38 offshore turbines in Europe. Since its full-scope OEM agreement ended, it has managed inspections and repairs directly, with gaps in condition history from the contract years.

The challenge

• One severity band. 99 findings were rated Cat 3, with no Cat 4 or Cat 5, and no way to rank them.
• One recurring problem. Of those 99, 96 were leading edge erosion and three were delamination.
• No raw imagery. Decisions rested on the damage list and the rate card.
• A list that rebuilds itself. Repairing only Cat 3 would leave 456 Cat 2 leading edge findings.
• A big number. Repairing every finding individually would cost €3.18M.

What they did

We applied the Repair Now Ratio (RNR) to every finding: the extra cost of leaving it a year, divided by the cost of repairing it now. Above 1.0, waiting costs more than the repair. Findings that justify a technician visit on their own anchor a campaign, and neighbours join only where access is already paid for.

1. 01
   Structure

   The damage list and rate card were structured for all 1,123 findings.

2. 02
   Price the delay

   The Repair Now Ratio was applied to every finding individually.

3. 03
   Test the scope

   Anchors and adjacency from 3 m to 50 m were tested in an interactive repair scoping tool.

4. 04
   Plan

   Two campaigns were presented, with the leading edge programme phased over five years, and reviewed together with the customer to align blade management and repair planning.

The results

• Campaign one anchors on the three Cat 3 delaminations. With the vessel mobilised, a 20 m adjacency covers 21 findings for €67,200, at RNR 1.47.
• Campaign two is a fleet-wide leading edge programme: 539 findings on all 38 turbines, sequenced over five years, at RNR around 3.00. Left a year, they would cost about four times as much.
• Widening campaign two from 3 m to 50 m added findings at a marginal RNR of only 0.03, so it stays a clean leading edge scope.
• Every year of the programme lands between RNR 2.84 and 3.37, at about €365k a year.
• Deferring everything a year would add €4.98M, against €3.18M to repair every finding now.

All of it was built on data the operator already owned, with no raw images. The Repair Now Ratio gave the team a clear order of work, a budget for each year and a reason for every repair.