Temperature shock in a 36-inch steam pipe shut down one coal plants July 1 and Portland General Electric (PGE) doesn’t know when the Boardman, OR, facility will be back. In addition, another plant partially owned by PGE shut down the same day following another incident.
PGE said a temperature shock in a 36-inch steam pipe at its coal plant in Boardman knocked the pipe out of its hangars. The “thermal water hammer,” caused by hot steam coming into contact with cooler liquids and gases, could leave the plant offline for at least a month, the utility said.
PGE operates Boardman and takes 65 percent of its 575 megawatt output, enough electricity to supply 250,000 customers.
PGE also owns 20 percent of two units at the Colstrip power plant in Montana, which is the second largest coal plant west of the Mississippi. An unspecified incident at one of the two units on the same day of the Boardman outage knocked out that unit. PacifiCorp also owns 10 percent of the output of the same unit.
The operator of the plant, PPL Montana, is in the process of working on an assessment.
Corson said no one was hurt in Boardman and no steam released. There are no cost estimates yet, but the company says it will likely be offline for at least a month for repairs. Meanwhile, from a reliability and price standpoint, Corson said PGE had been able to find good replacements for the output of both units.
“The market had been pretty liquid, so we’ve been able to respond well to having the plant offline,” he said.
The last unplanned outage at Boardman was in 2006, when cracks in a new turbine brought the plant down for months and led to a long fight over whether ratepayers or shareholders should pay for it.
“That happened in very different market environment, where gas costs were different,” Corson said. “We’re fortunate that gas costs are much lower today.