What happens when a wind turbine gets hit by lightning?

Wind turbines are particularly prone to lightning strikes, as they are usually the tallest structures above the landscape for a considerable distance, and lightning will tend to hit the highest point it can. And the effects if a lightning strike on a wind turbine can be devastating as this tweet from Twitter user @MikeCollierWX demonstrates.

Tulsa native Mike Collier is Chief Meteorologist for KJRH

In the video one of the blades of the wind turbine has been hit by lightning and gone on fire, which then spreads to the nacelle, which houses the generator, and from there to the tower. The wind turbine ends up basically destroyed. The lightning strike occurred in Cromwell, Oklahoma.

When lightning hits an unprotected wind turbine blade, it raises the temperature dramatically, up to 54,000 ºF according to InterNACHI, which can cause all manner of damage to the blade, including, as was likely the case in the video above, going on fire and then potentially destroying the entire turbine.

But lightning can also damage the turbine’s control system, including its motors for steering into the wind. The electronics in the turbine can also be damaged by a lightning strike, as can the electric generator itself. Finally, the batteries used in the turbine can be adversely affected, and in a worst case scenario, explode.

Lightning protection systems for wind turbines

Given their high vulnerability to lightning strikes, wind turbines are often fitted with protection systems, that, if they work properly, will protect the turbine from strikes. The basic idea is to ensure the blade gets hits in the right place, and the strike is conducted safely down the blade and from there to the ground (earth). According to Alex Byrne, a wind energy engineer specializing in operational excellence at DNV, speaking to Power Technology, “If things are designed and tested properly, then damages should not be expected in the field”, though she says that defects in manufacture and installation can lead to the protection systems not working properly.

However it’s important to note that turbines are actually hit fairly regularly, on average a blade will take 20 strikes in its lifetime, and very few strikes will result in the damage seen in the video.

Lightning is a serious issue for wind turbines

The seriousness of the threat lightning poses to wind turbines can be seen from a German study that estimated 80% of insurance claims in the industry were related to lightning strikes. It should be noted that the study dates from 1995, so technological developments and better lightning protection systems may well have improved the situation, although reporting extraordinary warranty costs of €175M (the dollar is about level with the euro at the moment) Vestas’ CEO Henrik Anderson said “high intensity lightning” was responsible. Vestas is a Danish manufacturer, seller, installer, and servicer of wind turbines

The overall take-away: lightning strikes can destroy or seriously damage wind turbines, but lightning protection systems can majorly mitigate the issue.