Canadian fires cause close call for New England power supply
It now appears that the unprecedented forest fires that scorched Canada beginning in June came perilously close to having a devastating impact on the Northeast U.S. power grid.
In the last week, officials at the independent system operator that runs the New England grid have revealed that on July 3, four transmission lines from Hydro-Quebec shut down because of raging fires near James Bay in northern Quebec. The loss affected the grids in New England and New York as well as Quebec, New Brunswick and Ontario in Canada.
While ISO-New England was able to recover without any power loss, as did New York’s ISO, it’s arguable that had the timing been even slightly different, a catastrophic power failure could have occurred.
“If we were at peak load, it would have been a major problem,” said Dave Doot, counsel for the New England Power Pool – NEPOOL – a voluntary group of several hundred power participants. He was among those briefed about the July 3 events by ISO-New England at NEPOOL’s monthly participants committee meeting on Aug. 2. “In other circumstances there could have been load reductions or rotating blackouts or brownouts. Clearly ISO was able to manage this one.”
In fact there were major power losses in Canada over the next two days including in Montreal, where the subway system went down, hospitals were affected and people were trapped on stalled roller coasters. About a half-million customers lost power at the peak.
The main Hydro-Quebec line came back up later on July 3, but went back out the afternoon of July 4 and stayed out until late on July 6 during which time ISO-New England called on back-up generation –including plants operated by NRG Energy in Connecticut.
Working in ISO-New England’s favor were several factors that could be categorized as sheer luck. While July 3 was a hot day, topping out at 88 degrees at Bradley International Airport, with 93 percent humidity and a dew point of 71 degrees, the transmission lines went down around 5 p.m., as demand was beginning to drop. ISO said the peak demand for the day was 22,627 megawatts, which occurred between 4 and 5 p.m.
July 3, a Wednesday, was also just before the four-day Independence Day holiday weekend, and demand likely was lower than it might have been on other Wednesdays. The next five days were in the 90s with even higher humidity, but one was an official holiday, another was a de facto holiday and two were weekend days –- all likely with lower demands than normal.
What the ISO reporting on the incident refers to as imports from Hydro-Quebec –- a total of 1,750 megawatts that accounted for nearly 8 percent of the peak demand -– were lost over five minutes instead of all at once, which might have been harder to overcome. ISO spokeswoman Ellen Foley said by contrast, in the 2003 Northeast blackout, it took seven seconds for the loss of power in the Midwest to reach New England.
Foley said replacement generation was in place within 11 minutes from the reserves ISO always has in place.
“Is this unusual? Yes, this is unusual, but it’s not something we don’t plan for,” she said. “We train for this. Could it have been worse? Yes. Could it have been better? Yes.”
But others worried that had the situation occurred two weeks later during the heat wave that set power demand records and near-records or even on a more normal Wednesday or just an hour earlier when the demand was higher, the results could have been dire.
“If that had happened, it very quickly would have been more serious,” Doot said.
Foley would not engage in hypotheticals. “I cannot speculate on how the system would have operated under different circumstances. We followed operating procedures.”
Mike Jacobs, a senior energy analyst and grid specialist at the Union of Concerned Scientists, said it was important to note that multiple power pools were affected by the transmission line shutdown. That meant the potential for the situation to cascade into something much larger was there.
He specifically pointed to a key reading called the frequency, the system’s rate of oscillation. It should be 60 hertz. During the transmission loss, it dropped to 59.91, which Foley admitted was a large loss.
“It’s very critical if we lose a major power plant and lose frequency,” she said. ”We lose the stability of the system. It could create cascading outages.” She said there are procedures to shed load if the frequency drops too far.
“We were not near that situation.”
But that frequency drop jumped out at Jacobs. “The risk was that we would have had an outage that would have lasted a few hours across all the ISOs,” he said.
What also concerns him is Connecticut’s and other northeast states’ intentions to move toward using even more hydro from Canada. Not that it’s an inherently bad form of energy, Jacobs said. He worries it could put too many energy eggs in one basket.
“The broader challenge is for all these operators and the utilities and state regulators to find and promote flexibility,” he said. “The inclination for each of them to increase their reliance on a central system like Quebec hydro doesn’t increase flexibility, it reduces flexibility.”
Ironically the July 3 events occurred just days before the U.S. Department of Energy released a major report on climate change and the impact of extreme weather on energy vulnerability. Among the concerning factors it cited was exactly what happened in Canada -– increased incidences of forest and wild fires that damage or otherwise incapacitate transmission and/or infrastructure.
And it came as the region has seen increasing problems at its nuclear plants from cooling water that has become too warm. The Millstone Nuclear Generating Station had to shut down one of its units for 12 days last summer due to warm intake water levels. The Pilgrim Nuclear Power Plant in Massachusetts came close to that point earlier this summer, and Vermont Yankee has also faced climate-based problems.
“It certainly speaks to resiliency and reliability and the need to strengthen and harden the grid to be prepared for weather events,” said Department of Energy and Environmental Protection spokesman Dennis Schain of the July 3 events. “We believe we will see more extreme weather, and we need to make sure we have a broad mix of energy resources to tap.”
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NEPOOL’s Doot, while noting general reaction to ISO New England’s handling of the power situation of July 3 was positive, was mindful that questions about climate change and the grid’s ability to handle the increased demand that goes with it are legitimate.
“We are running closer to wire, no pun intended,” he said. “We are likely to have more and more of these events. We lucked out this time. We lucked out.”
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