Consumers Energy told regulators in Michigan that "unique and extreme weather conditions" during a safety venting fire-gate process caused a compressor station (CS) fire in January.
In a 29-page report to the Michigan Public Service Commission (MPSC), the Jackson, MI-based utility said the Jan. 30 fire at its Ray CS in Macomb County began when an abnormal operating condition was detected in the station's control system. A plume of natural gas was released as part of the emergency safety fire-gate process, but 20-28 mph wind gusts pushed the plume directly toward a thermal oxidizer at the facility, causing the plume to ignite.
"The fire and damage at the Ray Station was precipitated by a safety venting fire-gate process that has been proven safe and effective in the past," Consumers said, but added "the process became hazardous to the station equipment" because of the weather on Jan. 30. "This new failure mode has now been added and new risk mitigation countermeasures will be implemented at the Ray Station and across the fleet to further enhance resilience and help to avoid failure under extraordinary circumstances in the future."
MPSC ordered the utility to submit a report, and Consumers hired a third-party consultant to perform an investigation. The findings aligned with the utility’s analysis.
Although there were no injuries, Consumers said the fire required it to issue its first-ever operational flow order for gas transportation customers. At the time, the utility said it had 61.9 Bcf of working gas inventory, above its target of 61.4 Bcf during a typical winter. Michigan was hit with a cold snap in late January.
The utility told the MPSC that it spent $10.6 million on emergency gas purchases for Jan. 30-31 gas days following the incident. It also reported that the amount of lost and unaccounted for gas as a result of the fire was 3,260 Mcf, which cost an estimated $14,000.
Consumers also estimated that it would cost $14 million to replace the Ray Plant 2 dehydration system and an additional $4 million to repair or replace the Ray Plant 3 support systems. The utility said it was working to refine the repair costs in the near future as additional information becomes available.
Consumers provides natural gas to 4.1 million customers. The utility operates nearly 2,500 miles of transmission pipeline and more than 27,000 miles of distribution pipeline.