Fire at Akuo's O'Mega 1 floating solar plant in France

What happened

A fire broke out on 30 January 2022 at the O'Mega 1 floating solar plant in Piolenc, Vaucluse, southeastern France, operated by developer Akuo. Storm winds from the North Sea, with gusts up to 80 km/h, exposed the water body to several days of violent wind. Swell and repeated friction exposed the conductors of cables linking modules to junction boxes, causing a short circuit on one three-panel floater. The affected inverters shut off, but three floats ignited.

Passers-by saw smoke and called the fire brigade, which could not intervene for safety reasons because the fire was electrical in a water environment. Akuo shut the plant down manually from the point of delivery, and the fire went out. About 15 MW of the 17 MW plant was returned to service while the damaged section was repaired.

Contributing factors

Maintenance teams had observed wear on the cables linking modules to the transmission terminals since October 2021. Akuo said it had underestimated the medium-term effect of wear and the weather risk. Replacing all the cables on the site was a large operation, so it was not adopted immediately, and wear progressed further than expected before the rupture during high winds.

Lessons learned

1. Where wear is observed on floating PV cabling, bring forward repairs rather than deferring them, because swell and friction can accelerate damage.
2. Include storms and sustained swell in maintenance risk assessments for floating arrays and inspect cabling after severe weather.
3. Fit protective sheathing where cables rest on metal structures, and design cable supports for water movement from the outset.
4. Plan for limited firefighting access to electrical fires over water, and for rapid isolation of the plant from the point of delivery.

More lessons on weather and external hazards, electrical protection and isolation, fire suppression and firefighting, from every incident on the register.

Source

pv magazine (pv-magazine.com)