A power watch issued for Newfoundland and Labrador Hydro customers on the Avalon Wednesday morning will stay in effect until Friday.

One of three generating units at the Holyrood plant was taken offline for repair early Wednesday morning. 

Dawn Dalley, Nalcor Energy's vice-president of corporate relations and customer services, says that's not an unusual event this time of year.

"It's very technical, but it looks like a boiler tube leak," she told CBC Radio's St. John's Morning Show

Dawn Dalley

Nalcor Energy vice-president Dawn Dalley says customers want to be warned about power issues in advance. (CBC )

Crews, she said, are working to assess the damage and should know in the coming days how long repairs will take.  

With cold temperatures forecasted again for Friday, Hydro said it will continue a system watch until then and advise customers of any changes.

Dalley said the incident was handled differently "this time around" compared to outages two years ago as the Crown corporation put "additional generation online early."

"We've had additional generation on last night, our gas turbines are up and running — just at the ready in case something does happen that we'll be able to respond quickly," she said.

Lessons learned from #DarkNL

​Dalley said after the rolling blackouts and other power setbacks of recent years, the corporation has learned customers want to be warned ahead of time.

"What it says is we're watching the system closely, load is high and we want you to know that we're monitoring it closely. A bit like if you were driving your car and your engine light came on," she said.

Dalley said power generation across the island is fine.

"This really is just an issue for the Avalon Peninsula. It's the nature of how our system is. We have a lot of people on the Avalon, lots of electricity usage on the Avalon."

Scale back

The utility is working closely with Newfoundland Power and Dalley said, if the situation worsens, a power warning will be issued.

Dalley said heat and hot water are the biggest drains on the system.

Customers were asked to turn down their heat by a couple of degrees and to turn off any unnecessary appliances Wednesday morning. 

By afternoon, Hydro no longer requested customers conserve electricity, but said it's always a good idea to "be prepared to conserve in the event of a status change."

Hydro forecasts that peak times of demand on the system are between 7 and 9 a.m., and 5 and 7 p.m.

Cold weather is expected again on Friday. Hydro said it will continue monitoring the system and will notify customers of any changes.

Customers can monitor the NL Hydro website for updates, as well as its Twitter and Facebook pages.