Wind turbine blade breaks after undetected lightning damage

Apr 2026Published 26 Sept 2026Responsible editor: Chief Editor

SignificantMechanical

Estimated damageEstimated by the register's adjusterHow? Know the real figure?

turbine out of service for about •• daysShown in the record →Full estimate

From the recordRoot cause Failed part

Where: Oga City, Akita Prefecture
What: Wind turbine blade broke during operation
Cause: Lightning strike on 20 March damaged the blade

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What happened

On 12 April a blade on a wind turbine in Oga City, Akita Prefecture, broke during operation. The operator reported to the Ministry of Economy, Trade and Industry that a lightning strike on 20 March had damaged the blade. Continued running weakened the structure until it failed. An inspection on 4 April did not detect the damage because the turbine remained rotating during a ground-level visual check.

Contributing factors

Lightning damage reduced blade strength. The 4 April inspection was performed while the rotor was turning, so the fault was missed.

Lessons learned

A ground level visual check cannot detect blade damage if the rotor keeps turning, so stop the turbine for all blade inspections after lightning.
Lightning damage can weaken a blade enough to cause failure weeks later, so confirm no damage before return to service.

More lessons on weather and external hazards, from every incident on the register.

Not yet known

Turbine model and age
Downtime after the blade broke
Cost of repair or replacement

This entry is updated when these are reported. Get an alert for the next one like it.

Source

topics.smt.docomo.ne.jp

Published 2026-09-26. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.

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Chart to reuse with this story: Wind (onshore) incidents by year, free with a credit (PNG).

The record behind this entry

The record behind EIR-1318 holds the operator, the root cause and what failed as fields you can filter, count and export, with its 2 sources and their verification status. The cause is not hidden: the contributing factors above give it as the sources report it. The record adds it as a field. Companies are named in the roles the sources give them. Being named is not a finding of fault.

Operator: •••••••••
Failed part: •••••••
Sources: ••••••••••

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Wind (onshore) incidents in Japan: 5 entries, with a free alert for the next one.

Wind turbine fires: the counts, the latest entries and a free alert for the next one. Also: wind turbine blade failures and lightning strikes on energy assets.

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