The nuclear power plant near Richland is putting enough electricity on the grid to serve about 40,000 more homes than it could five years ago.
The difference has been the maintenance and improvements made during its refueling outages.
Testing has confirmed that the Columbia Generating Station’s output increased by at least 28 megawatts following the refueling and maintenance outage that concluded in late June, Energy Northwest announced Tuesday.
That’s in addition to the 20 megawatts gained when the main steam condenser and other projects were completed in the 2011 refueling outage.
The bulk of the increase from the last refueling outage came from installation of a new feedwater flowmeter, which measures the amount of water flowing through the reactor core. The more water that can be used, the greater potential power output.
Over time, the calibration of the previous flowmeter degraded and water flow was limited as a result to make sure it remained within limits. The new ultrasonic instrumentation provides accurate measurement of the water flowing to the reactor core and gets the reactor to a true 100 percent power output, according to Energy Northwest.
Before the most recent outage began in May, Energy Northwest officials had conservatively estimated the increase in output capacity that could be gained by installing the new flowmeter at about 5 megawatts, about a quarter of what testing has shown.
The additional megawatt increase to 28 megawatts is mostly from work on valves throughout the plant during this year’s outage.
Five years ago, Energy Northwest was calling Columbia a 1,150 megawatt plant. As of Tuesday, it is calling it a 1,190 megawatt plant, a conservative number to make sure it can continue to produce that output.
“These are extra megawatts with almost no incremental cost and zero carbon emissions,” Brent Ridge, Energy Northwest’s chief financial officer, said in a statement. “Because of that they are incredibly valuable to the region’s ratepayers.”
Columbia Generating Station, the third largest generator of electricity in Washington state, sells its electricity at-cost to Bonneville Power Administration. More than 90 utilities, including those serving Richland, Kennewick and Pasco, receive a percentage of its output.
Energy Northwest shuts down every other year to replace about a third of its fuel and to do maintenance that would be difficult or impossible when the plant is operating. Between its last two outages, it operated for 683 days straight at a more than 98 percent capacity factor.