Coal silo collapse takes Vectren unit off line

OREANDA-NEWS. July 27, 2016. US utility Vectren has suffered a coal silo collapse that will likely have one unit off line for weeks.

The mishap occurred on 24 July at the F.B. Culley power plant, which is operated by Vectren subsidiary Vectren Utility Holdings in Warrick County, Indiana.

The bottom cone of the silo, similar to a funnel through which coal enters the silo, broke loose and crashed to the concrete floor. The cone took out cables, wires and steam lines as it fell, resulting in "severe damage" to Unit 3 of the plant, the company said.

Unit 3 was initially expected to be out of commission for four to five weeks, but there are now indications that repairs could take seven to eight weeks or more. The assessment is ongoing and cannot be completed until the spilled coal is removed. Unit 2 automatically shut off as a safety backstop when Unit 3 was damaged but is now back on line.

The company is still analyzing the cause of the accident, but Vectren officials do not believe the incident was the result of improper maintenance.

The company has other units on line but is also importing power from the Midcontinent Independent System Operator to replace the lost generating capacity. Vectren said it is too early to estimate the financial fallout from the incident.

The company does not expect the accident to affect its coal purchases. Last year, the Culley plant took 803,085 short tons of coal from Oaktown Fuels Mine #1 in Oaktown, Indiana.

Unit 3 was built in 1973 and has 270MW of capacity, and Unit 2 was built in 1996 and has 90MW of capacity. The plant previously had one other unit which Vectren retired in 2006. The facility has six coal silos including the damaged structure.

The Culley plant is one of two stations serving Vectren's 140,000 electric customers in southwest Indiana via the utility Vectren South.