Offshore Wind Blade Winter Inspections

by Frank Haggerty

18 hours ago

Offshore Wind Blade Winter Inspections 
 
Most ocean wind blades are over 100 meters (about 350 feet) and are hybrid blades.
 
Hybrid wind turbine blades are manufactured by combining materials like carbon fiber and fiberglass. The purpose is cost-efficiency, flexibility, strength, and stiffness. 
 
The blades are built in molds with structural foam and balsa wood infused with resin to create a lightweight, aerodynamic structure.
 
In July 2024, a hybrid blade broke off the coast of Nantucket, dumping 50 tons of fiberglass, foam, and balsa wood into the ocean environment. The blades had never been tested in an ocean environment. Over 60 blades were identified as having manufacturing defects.
 
Since the accident, enhanced monitoring was added, including a new algorithm for existing fiber-optic sensors to prevent future blade failures. 
 
The recent winter temperatures from Maine to Rhode Island have seen temperatures in the single digits. 
 
Hybrid wind turbine blades are prone to cracking in cold weather due to extreme brittleness, ice-induced uneven loading, and fatigue from low temperatures. Ice buildup on leading edges creates structural imbalances and causes rapid micro-cracking, which could lead to severe blade failure. 
 
Cold weather increases "torsional stiffness" and induces fatigue, requiring testing.
 
Following the 2024 Nantucket failure, rigorous inspections should take place.