[4] BPA Explains July Power Shortage
Two representatives of the Bonneville Power Administration say they will manage resources more conservatively after dodging a potential power shortage in July. BPA managers Rick Pendergrass and Dave Armstrong explained how the agency got in the power pickle at last month's Northwest Power and Conservation Council meeting in Missoula.
"We were still in the tail end of the runoff," said Pendergrass. "Inflows were declining, but still strong. Headwater projects--Libby, Dworshak, Grand Coulee, Hungry Horse to some extent--were full or nearly full and passing inflow. Some of those projects, at, or near turbine capacity. Grand Coulee and Chief Joe were at full load during heavy load hours trying to move water through the system."
He said models were indicating the need to move water and energy throughout the week of July 18 to keep the system managed "as we were coming off the end of the runoff."
On the morning of July 18, Pendergrass said regional temperatures were in the 90s. He called it "one of the first warm days in the summer," and said the initial forecast showed about an 800 MW shortfall for a couple of hours in the afternoon.
Three hours after the sale, at about 9 a.m., BPA's real-time marketer put out a bid for about 120 mills, 50 mills above market, to cover the afternoon deficit, but got no response. So BPA called the Corps of Engineers and the Bureau of Reclamation for added generation to cover the deficit. Pendergrass told the council that they found about 200 MW from a combination of Hungry Horse, projects on the Willamette, and Libby.
"In talking with the Corps, there was concern about whether we'd have to use emergency actions to cover load in the afternoon," Pendergrass said. He said it was decided to set up an emergency meeting of the Technical Management Team (TMT) for noon, to initiate discussion before any action was taken.
Just before 11 a.m., about 250 MW was booked for the afternoon, and BPA told the Corps the market was responding and it looked like the deficit could be covered and that they didn't see the need for a discussion of emergency actions. But it was decided other contingencies might be faced, such as a lightning strike at Libby, so the meeting was held.
At 11:30, the remaining 400 MW was booked to cover the rest of the afternoon load. At the TMT meeting, members were told that the loads had been covered by market purchases, and barring any other contingencies, the situation was covered. Pendergrass said priorities of emergency actions were discussed, "and that discussion is still continuing."
Other factors that contributed to the day were a planned power outage over the weekend that had BPA's marketer and power scheduler in the emergency scheduling center in Ditmer, at Vancouver. They were having some IT issues and were concerned about the validity of the data, Pendergrass said. Communication with analysts and managers was more difficult since it was all by phone, he added.
The lower river was also close to empty on the morning of July 18, though that was not uncommon. McNary Pool was also at the bottom of its operating range to help with work on the Yakima River bridge.
Pendergrass said another factor was the loss of flexibility at McNary and the lower Snake projects from the court-ordered spill, which made between 1500 MW and 2000 MW of short-term capacity unavailable.
BPA's Dave Armstrong said the initial non-response to BPA's request for power was likely due to other power players making sure they had their own loads covered for the day. But after prices rose, projects were coming on line that weren't operating in the morning, he said.
"So, the market developed, and we're finding when we get into those situations, we won't be as able to quickly cover a future set of hours, but as you get closer, and we've seen this in the past, you are able to get the energy you need as long as the region as a whole isn't in a deficit situation," he said
He said there was plenty of energy available well before the period of concern. He said BPA got a lot of calls from marketers and actually turned down a lot of power during this period.
Washington Council member Tom Karier asked the BPA officials if they would do anything differently today with the same signals they saw before the July 18 situation.
Pendergrass said they'd be careful about scheduling a pool restriction on McNary for a Monday morning, and would like to keep the lower river "a little fuller" to increase the flexibility they no longer have at other projects.
He also said they would likely be more conservative on their approach to surplus sales, which got Karier's attention. In response to another question, the BPA manager did acknowledge that they had made some surplus sales at the start of the month and on the "day-ahead" market, including the Friday before the July 18 squeeze.
"That's not unexpected, it will happen occasionally," said Pendergrass, who said BPA will approach the market more conservatively now that they better understand the loss of flexibility on the lower Snake.
But sources told NW Fishletter that at 6 a.m. on July 18 BPA sold a "surplus" 400-MW, 11-hour block in the market.
Sources also said that the VISTA forecasting model used by BPA may have played a role in developing the over-optimistic scenario about surplus power, and had overestimated surpluses for several weeks.
Later that day, the administration paid nearly twice the price to re-acquire the power they sold as excess in the morning. The cost of filling the deficit hole that afternoon amounted to $110,000.
Armstrong confirmed later that BPA had sold some power the morning of July 18, and that a lack of communication during a shift change played a role in the course of events. -B. R.
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