Windindustie in Deutschland, a project of the Federal Wind Energy Association (Link https://www.wind-energie.de/), has described in German how the new repair solution for blade root insert works. The repair method is a cooperation between CNC Onsite and its partner We4Ce.

Loose blade root inserts are a rising problem on wind turbines and it affects not just older turbines. Usually, loose bushings occur after the warranty period.

The damaged inserts need to be repaired soon to keep the blade from flying off, a worst case scenario. But how do you find out if blade root inserts have become loose?

Loose blade root bushings (another word for inserts) are usually detected during the regular inspection of the blade root connection.

Cracks in the sealant between pitch bearing and blade root can indicate a loose bushing. This can create gaps. Sometimes this is referred to as “gapping” by technicians.

The maintenance engineers and technicians will therefore alert the wind turbine owner to the problem of loose bushings. So, how do you repair these bushings?

We4Ce as blade root specialists and CNC Onsite’s partner has long been researching and testing numerous blade root repair solutions. The key criteria have been reduced costs and low impact on the environment.

This is what drove the development of the blade root bushing repair service, which is a solution that can retrofit damaged and loose bushings directly on-site within the windpark.

Up until now, the entire blade has had to be shipped to the manufacturer for repair with the associated costly logistics, CO2 emissions and downtime.

The downtime of sending the blade away for repair takes many months. CNC Onsite has estimated that downtime could cost 5,000 Euros a day per MW (example 4MW 4 x 5,000 = 20,000 Euro/day).

This comes in addition to the high transport cost.

With newer wind turbines, owners often choose to buy a new blade and scrap the old one.

Meanwhile, the wind industry is calling for a ban on the landfilling of decommissioned blades in Europe from 2025. In this context, the new repair solution from We4Ce fits right in. Our solution is patented and is based on infusion of epoxy resin to fix the retrofit bushing solidly.

Damage to blade root bushings is enough of a problem to warrant more research. This issue is rising, also in offshore turbines. It affects turbines of all ages, from 1.5 MW to 3 MW and 40-m to 60-m blade lengths and even longer blades.
We4Ce/CNC ONsite can act quickly to repair loose bushings and we work globally. We operate a large-scale repair service for windparks with ten or more rotor blades needing repair.

Read about the solution as reported by Windindustrie in Deutschland:
https://www.windindustrie-in-deutschland.de/unternehmensmeldung/cnc-onsite-mit-vor-ort-reparaturloesung-fuer-rotorblattwurzeln-auf-der-husum-wind
(September 2023)