Power supply overruns demand in NL1/14/2013
People across Newfoundland spent at least some portion of the day without power Friday, as the amount of energy demanded by homes and businesses on the island was surpassed by what was being supplied to the isolated grid.
As of deadline, about 65,000 Newfoundland Power customers remained without power, 40,000 of those in the St. John's area.
The power shortage was due to the failure of multiple Newfoundland and Labrador Hydro generating units and power plants.
The main problem came around 6:45 a.m., when the Holyrood Thermal Generating Station went offline.
According to Karen O'Neill, a spokeswoman for Nalcor Energy - Hydro is a Nalcor subsidiary - there was a problem with equipment at the terminal station at Holyrood. That problem caused a loss of power at the plant next door.
Without power, the generators can't run.
The Holyrood power plant operates 24/7 with an average 100 to 110 employees keeping the plant running as needed. However, the adjacent terminal station is filled with equipment dealt with by an outside team, with different training - training specific to terminal stations.
That team is located in Whitbourne, since that location is central to multiple island terminal stations.
It took several hours to get the terminal station experts to Holyrood when needed this week, as a result of snowdrifts and whiteouts on the Trans-Canada Highway - the result of the weather system hitting the province.
Exactly what led to the failure at the Holyrood terminal station is still under investigation.
As of 5 p.m., repairs were underway and the power plant was expected to take several hours to bring online, beginning the feed to Newfoundland Power for distribution to that company's customers.
Yet Holyrood was not the only headache for Hydro during the storm. Generating units at Upper Salmon and Cat Arm also went offline.
"Not sure exactly the issue at each of these locations," O'Neill said when asked about the smaller power plants.
Cat Arm is on the southeastern area of the Northern Peninsula and is the third largest hydro plant in terms of capacity, able to produce 127 megawatts (MW). Upper Salmon is a smaller plant, west of Bay D'Espoir and able to put out 84 MW. In comparison, Holyrood can put out about 500 MW at maximum capacity.
Just as with the problem at the terminal station at Holyrood, the company is investigating the exact cause of the loss of capacity at its smaller plants.
The shutdowns at the smaller hydro stations may have been caused by irregularities in the system as a result of the storm.
"If the system identifies there's issues there ... there's tripping ... the system can do things to protect itself," O'Neill said.
Outages were expected overnight as the power supply and service system was normalized. Newfoundland Power spokeswoman Michele Coughlan said power would be rotated to customers until Holyrood is brought back online by Hydro.
"Until they do that and we have a supply of power, we won't be able to restore power to (all) customers," she said shortly after 6 p.m.
As for who recovered power during the day, Coughlan said that was determined by technical aspects of the system and not arbitrary selection.
Asked about issues outside of the supply, she said there was a problem with just one feeder power line to Cape Broyle, affecting about 1,200 customers, before Holyrood was lost.
Meanwhile, customers have been asked by both Hydro and Newfoundland Power to keep their energy usage at a minimum to help Hydro and Newfoundland Power bring operations back to normal over the coming days.