Newfoundland and Labrador Hydro continues an extensive investigation into a serious problem at the Holyrood generating plant.

One of three oil-fired generators was damaged in a blizzard that shut down part of eastern Newfoundland on January 11. Having the unit out of service could pose problems for customers, as January and February are considered to be part of the peak season for electricity demand.

Hydro suspects the problem was an electrical fault, but it continues to review the issue.

Vice-president of regulated operations, Jim Haynes, said the unit will be out indefinitely including the rest of the winter season.

Haynes said the machinery at the plant is more than 40 years old. He said the plan is to repair, rather than replace the equipment.

"To go out now and try to purchase a new thermal plant would be years," added Haynes. "But the repair time would be less than that. We don't have a definitive time frame - but we do overhauls on a regular basis [on those machines] - and they take several months."

Hydro says it will draw on reserve power if conditions warrant, and may have to rotate power for short periods, if it cannot reduce demand during peak times.

"On a bitterly cold day when the wind is up and consumers are using more electricity .. or if there's a problem with another generating plant or a unit somewhere, that's when we might need to consider this. We just want to moderate the demand," said Haynes. "But that's the last thing we would do. We would exhaust all other options to meet the customer demand without any inconvenience."