The Boardman Coal Plant is back online after a thermal water hammer knocked a 36-inch-diameter pipe off its hangers July 1, causing $10 million in damage.
Portland General Electric, which operates the facility in Boardman, OR, and owns 65 percent of its 575-megawatt capacity, released the repairs July 31. Spokesman Steve Corson said it remains up in the air as to how the cost will end up divided among PGE and minority owners Idaho Power, Power Resources Cooperative and Bank of America.
Thermal water hammer occurs when hot steam carried in piping comes in contact with cooler liquids and gases, causing the bubbles to condense rapidly which leads to a sudden change in pressure and sometimes implosion. While not uncommon in the industry, Corson said it is the first incident of that magnitude in Boardman.
No workers suffered an injury, and the pipe did not rupture or release any steam. No customers ended up affected by the shutdown, Corson said, though PGE spent somewhere between $3 million and $4 million on replacement power from its own generation and other wholesale sources.
The utility draws 374 megawatts from the plant, which is enough for 250,000 residential customers.
“We’re pleased we were able to bring the plant back online and get that power flowing,” Corson said.
The Boardman plant has 110 full-time employees. Plans right now call for the plant to end coal-fired operations by 2020 and PGE said in June it will build a new 440-megawatt natural gas plant adjacent to the current facility. Construction is on tap to begin early next year, Corson said.
PGE serves more than 800,000 customers in Portland, Salem and the northern Willamette Valley.