BOULDER, Colo. — Two sources of power for Boulder’s wastewater plant were shut off by Xcel Energy, nearly causing raw sewage to flow into Boulder Creek.
When Xcel utilized public safety power shut-offs (PSPS) for the first time on April 6, it shut down power to Boulder’s Water Resource Recovery Facility (WRRF).
“We can’t treat wastewater without power,” Boulder’s Deputy Utilities Operations Director, Chris Douville, said. “It’s eerily silent when the power is off.”
Douville described the near miss on April 6 that saw the treatment tanks nearing an overflow stage.
“We initially anticipated we had about two hours before we would spill,” Douville said. “The water level in this tank rose within 10 inches of this overflow rear plate.”
He said that several city staff were in contact with Xcel ahead of the planned outage.
Xcel proactively shut off power to 55,000 customers in seven counties on April 6 during high winds, with Boulder County experiencing the most outages.
“We were communicating with them several hours before we lost power,” Douville said. “It took a number of elevated conversations, all the way up to the top within our organization, as well as Xcel’s.”
Boulder’s WRRF is powered by two substations.
According to Douville, half of the facility is powered by one substation, half is powered by a second substation and if one goes down, the facility can be run by number two.
“This was the first extended outage where we’ve lost both substations,” Douville said. “We were under the assumption that we lose only one power feed because of our arrangement with Xcel.”
That arrangement is a 2006 agreement between the city and Xcel for “dual service facilities,” essentially two sources of power.
That agreement saw the city pay Xcel $140,000 in 2006 for the second power source and to reserve electrical capacity.
The city also pays $1,290 each month.
There is one section of the agreement that reads: “Xcel Energy reserves the right to remove preferred or alternate source from service for emergency situations at any time.”
The city and Xcel may bicker over the word “or.”
“Ultimately, they did restore power to the Niwot substation which allowed us to resume operation and avoid that spill,” Douville said.
But not without it being a close call.
There was a third treatment tank that was empty and under construction. Douville’s team was able to allow sewage to flow into that tank to buy some time before the tanks would overflow.
“We were within 10 or 15 minutes of spilling to Boulder Creek. So, it was very close,” Douville said.
Had the sewage spilled out, it would have gone directly into the stormwater system and Boulder Creek.
“We would consider it a severe public health crisis because Boulder Creek is heavily used by downstream entities for municipal use as well as agriculture, irrigation use, and recreational use,” Douville said.
Lafayette, for instance, can draw water from Boulder Creek to be used for drinking water. Boulder warned Lafayette of the problem with the power off.
“That would have been a concern for Lafayette. We were in close coordination with them in the moment to ensure that their water supply wasn’t compromised,” Douville said.
Just like so many customers that lost power on April 6, Boulder has concerns about communication before the power shut-off.
“If we knew a day or two in advance, there’s, actually, potentially a few things we could have done to get more ready for it, to prepare for it properly,” Douville said.
“Well, they’re coming to our council meeting tonight where we will be able to ask them questions about the response and what they’re going to do better and differently,” Boulder Mayor Aaron Brockett said.
Boulder City Council meets on Thursday nights and Xcel Colorado CEO Robert Kenney attended the meeting.
“I do think the message is getting through to Xcel loud and clear that we have to plan better, and so, I don’t expect us to end up in this situation again,” Brockett said.
“We will be approaching this important topic with Xcel to understand how reliably we can lean on that historical agreement or if we need to pursue and investigate other redundancy or backup power measures on top of what we already have,” Douville said.
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