The Canadian Nuclear Safety Commission was informed of the incident Wednesday around 5:30 a.m. and has staff onsite, closely monitoring the situation, according to a news release late Wednesday afternoon..

"At the time of this update, NB Power has not identified any reports of injuries, radiation contamination or spills into environment," said the commission, whose mandate includes protecting health, safety, security and the environment.

N.B. Power says further assessments are underway to perform the maintenance required to reconnect the station to the grid.

"This work poses no risk to employees, the public or the environment," it said in a news release.

N.B. Power spokesperson Dominique Couture did not immediately respond to a request for more information, such as when and why the power loss occurred, or how long it's expected to take to get the plant back online.

Point Lepreau, located about 35 minutes southwest of Saint John, is a 660-megawatt nuclear generating station and a major contributor to New Brunswick's electrical grid.

It's Atlantic Canada's only nuclear power generating station.

'Major equipment replacement' delayed until April

Point Lepreau was shut down for a week in August due to an undisclosed "equipment issue."

That outage came only five days after the generating station came back online following scheduled spring maintenance,  which dragged on for more than 100 days and wasn't completed as planned.

Supply and personnel shortages and more significant problems with station equipment than anticipated all contributed to the delay, Couture had said.

She said a 22-day outage is planned for April 2023 to deal with the unfinished work — a "major equipment replacement … to ensure predictable, reliable station operations going forward."

Shutdowns at Point Lepreau cost N.B. Power between $8 million and $10 million per week. (Mike Heenan/CBC News file photo)

According to N.B. Power's annual reports, unscheduled outages at the nuclear plant cost the utility between $28,500 and $45,700 per hour, depending on the time of year and market conditions, plus the cost of any required repairs.

But Couture said those are old costs related to the 4½-year, $2.4-billion refurbishment completed in late 2012. She could not provide an updated estimate. It will be reported as part of the financial statements in the annual report, she said.

According to filings with the New Brunswick Energy and Utilities Board, Lepreau has experienced 8,000 more hours of downtime than projected since the refurbishment, not including the spring outage.

Lepreau's operating licence was renewed by the Canadian Nuclear Safety Commission in June for 10 years. N.B. Power had sought an unprecedented 25-year licence renewal.

In October, the utility asked energy regulators to approve an 8.9 per cent increase in power rates for all its customers — the biggest rate hike in 15 years.

And that isn't changing.

But with "hedge gains," which refer to the risk-management strategy of hedging to offset potential losses or gains, and with the increase in hydro power, the utility is filing an application with the Energy and Utilities Board to reimburse customers a total of $15 million, effective April 1, 2023.

Factors out of utility's control 

"Due to changes that we're seeing in the market today, things that are outside of our control, the one per cent credit is as a result of improved hydro flows, as a result of improved export margins and a hedge transaction that we have benefited from in this year," said Lori Clark, acting CEO of N.B. Power. 

"So those are things that are a benefit to customers, and we're following the formulaic prescribed regulation."

Before now, N.B. Power had to absorb any "variances" after its rates were set based on forecasts of anticipated revenue and supply costs.

Before now, N.B. Power had to absorb any 'variances' after its rates were set based on forecasts of anticipated revenue and supply costs. (Mike Heenan/CBC News file photo)

But variances — in energy consumption, weather and exchange rates, for example — could result in either additional revenue or costs. According to N.B. Power, recent years have resulted in additional expenses that had to be absorbed by the utility.

Changes to the Electricity Act in 2021 mean there are now two variance accounts to track actual costs and revenue: the energy supply cost variance account and the electricity sales and margin variance account. 

The energy supply cost variance account represents the difference between the actual cost and budgeted cost of generating electricity. The electricity sales and margin variance account shows the difference between actual and budgeted revenue. 

Both changes would start April 1

The combined credit for the two accounts in the last fiscal year was $28.6 million. 

If the proposed $15 million reimbursement is approved by the EUB, it won't change the general rate application for the 8.9 increase, but it will mean a refund of one cent for every dollar they consume.

Clark said while the rate and the rebate are separate processes, they would both go into effect April 1. 

The variance will be calculated each year, said Clark, with some years possibly resulting in a credit like this year, or a "rate rider charge."

"This year, it's a good news story for customers," she said. "I think the important thing for customers [to know] is that this could go either way in the future."

That's putting immediate pressure on N.B. Power's finances, which are already burdened by an ongoing breakdown at its natural gas generating station that would normally help replace energy from the idle nuclear plant.

So far N.B. Power has said only that a "leak" was discovered in part of Lepreau's non-nuclear system that transports heat generated in its reactor to the plant's conventional boilers. The boilers produce steam that drives Lepreau's electricity generating turbines. 

However, the utility was hinting a fix would not be immediate.

"Investigation and assessments are underway in order to determine the path forward," it said in a statement Thursday.

The fossil-fuel-powered generating station at Coleson Cove, southwest of Saint John, is burning oil around the clock to produce electricity to help fill gaps left by two critical N.B. Power plants that are down for repairs, including the nuclear plant at Point Lepreau. (Roger Cosman/CBC)

Lepreau is N.B. Power's most important, and when it is operating its most lucrative generating station. But before the current shutdown, it was already having its worst year of production since coming out of a major refurbishment a decade ago.

An April maintenance outage that N.B. Power had hoped to keep to 10 weeks, dragged on for longer than 17 weeks as more issues than expected showed themselves.   

In evidence filed with the New Brunswick Energy and Utilities Board in October, N.B. Power revealed that the extended spring and summer outage meant it was only expecting to produce four million megawatt hours of electricity from Lepreau this year. 

That is one million fewer than last year and the lowest in any year since the plant emerged from a 4½-year refurbishment in 2012.

In addition, N.B. Power's natural gas generating station at Bayside in Saint John, which sometimes fills in for Lepreau during outages, also remains idle after suffering a catastrophic breakdown last winter.

N.B. Power's Bayside natural gas generating station, far right, broke down with a catastrophic turbine failure last January and isn't expected to return to service until this January. It normally would help replace lost energy from an idle Point Lepreau. (Roger Cosman/CBC)

N.B. Power initially planned for a return to service for Bayside this fall, but now says it won't be operating until January.

That will force NB Power into the marketplace to replace at least some of the energy from Lepreau which is normally priced at a premium during cold weather months.

N.B. Power's Dominique Couture said in an email that the utility will "be utilizing our interconnections to purchase energy as required."     

"Costs are unknown at this time," she wrote.

In the past N.B. Power has said shutdowns at Lepreau cost it $1 million per day, but that likely understates the expense it faces at this time of year.

The Massachusetts State House blanketed with snow during a nor'easter in Boston last January. During cold weather, New Brunswick has to compete with buyers from New England for electricity, usually at premium prices. (Nicholas Pfosi/Reuters)

N.B. Power executives have long pointed to the efficient operation of the Lepreau nuclear generating station as the key to its financial health.

The plant was meant to operate for 210,000 "effective full power hours" over 27 years following its renovation. However, at the end of March this year, it had logged 67,613, hours, a little more than 8,000 behind that original schedule.   

Troubles at Lepreau this year, including this week, have put it a further 1,300 hours behind that original target. 

Every hour of full production at Lepreau generates about $50,000 worth of electricity to sell.