Bird-triggered electrical fault sparks fire and major outage at California solar farm

What happened

On 5 June 2019 a fire broke out at the California Valley Solar Ranch, a 250 megawatt photovoltaic plant owned by Clearway Energy Inc. A California Department of Forestry and Fire Protection (Cal Fire) official said the fire began when a bird made contact with two overhead conductors simultaneously, completing an electrical circuit and producing a shower of sparks. The resulting fire spread through the surrounding dry grassland, burning approximately 1,127 acres.

The blaze damaged power poles and wires at the facility, knocking out 84 percent of its generating capacity. Clearway initially described the cause as an 'avian incident' without providing further detail. The company estimated losses at between 8 and 9 million US dollars. The plant was built by SunPower Corp, completed in 2013, and sells power to Pacific Gas and Electric. Injuries were not reported.

Contributing factors

A bird contacted two energised conductors at once, creating an electrical arc; dry grassland conditions in the surrounding area allowed the resulting sparks to ignite a large fire that spread beyond the immediate electrical equipment.

Lessons learned

1. Overhead conductors at solar farms need bird guards where large birds are active, as contact between two phases creates arcs and sparks.
2. Dry grassland around solar sites must have maintained firebreaks, as sparks from electrical faults can ignite large fires.

Not yet known

• Downtime duration after the outage
• Whether bird mitigation was already in place

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Source

Los Angeles Times (latimes.com)