Muskrat Falls lines failed 6 times since January

The Muskrat Falls transmission lines failed six times during the first quarter of 2025, although Newfoundland and Labrador Hydro says the problems had no impact on electricity customers.

The problems took on average nine hours to repair, according to the Crown utility, which is still unable to shut down the heavy oil-burning Holyrood Thermal Generating Station because of ongoing concerns about the reliability of Muskrat Falls power.

N.L. Hydro revealed the outages on the Labrador-Island Link (LIL), the vast 1,100km transmission system linking the Muskrat Falls dam to eastern Newfoundland, in a three-page letter sent to the Public Utilities Board (PUB) last Thursday.

According to the document, the LIL, a system carrying electricity over two independent lines or "poles," was completely offline during only two of the six incidents.

During the other four incidents, one of the two poles was still online and able to continue carrying Muskrat Falls electricity toward the Soldier's Pond substation outside St. John's. 

N.L. Hydro spokesperson Jill Pitcher said in an email that problems with weather and "control system component issues" caused the lines to trip three times in January, once in February and twice in March.

"Trips are experienced on all transmission lines," she said. "Transmission lines are designed to trip in response to a variety of system and/or weather conditions. The trips specific to the Labrador-Island Link in Q1 did not interrupt or impact our ability to supply our customers with electricity."

Since coming into service, the Muskrat Falls lines have experienced a series of problems, notably related to ice and high winds. Repairs have sometimes taken weeks, as some towers are located in isolated areas and difficult to access depending on the time of year.

N.L. Hydro has, however, repeatedly emphasized in recent months that the Muskrat Falls lines are becoming increasingly reliable and that new assets will always experience problems in the first years after commissioning.

In 2023, the utility announced a four-year program of repairs and upgrades to the LIL, pegged at $28 million. It said thousands of pieces of equipment had to be replaced or installed, including 1,308 turnbuckles used to regulate voltage and cable length.

The 824-megawatt dam is not currently operating at full capacity, as one of its four generating units needs to be completely dismantled, given a hydrogen embrittlement issue.

Unit 2 will be out of service until May, according to separate correspondence with the PUB.

The Holyrood Thermal Generating Station, the second largest industrial polluter in Newfoundland and Labrador, should have closed after the commissioning of the Muskrat Falls project, but will remain open until the beginning of the next decade, given continuing doubts about the reliability of the LIL.

N.L. Hydro promises to close the plant in the early 2030s, when it will have built a new combustion turbine at Holyrood and an eighth generating unit at the existing Bay d'Espoir dam. Those projects are expected to cost just shy of $2 billion, according to the Crown utility.