While the blizzard that hit Minnesota the night before Christmas Eve did little to damage Great River Energy’s transmission system, transmission partners that serve its member-owner cooperatives were not as lucky.
“The blizzard caused damage to transmission facilities owned by other utilities, which left 11 of our members’ substations without power for sustained periods,” said Mark Peterson, system operations manager at Great River Energy. “Due to white-out conditions, crews could not safely assess the damage until daylight.”
BENCO Electric Cooperative and South Central Electric Association were Great River Energy’s member-owner cooperatives most impacted by the damage to transmission facilities. In total, 678 South Central and 2,624 BENCO member-consumers experienced prolonged outages — some for as long as 28 hours.
Crews worked throughout Dec. 24 to restore service to BENCO and South Central substations and their members.
In times of crisis, cooperatives band together for the benefit of the greater good. In addition to Great River Energy, Steele-Waseca Cooperative Electric, Brown County Rural Electrical Association and Freeborn-Mower Cooperative Services provided mutual aid during the blizzard.
Great River Energy’s control room employees were in contact with the two member cooperatives as their situations evolved. Line technicians were also standing by to perform switching, which is the process of turning off the flow of electricity to sections of transmission line that needed to be repaired.
“It is fortunate we did not see much damage to Great River Energy’s facilities as a result of the blizzard, but with winds 60 miles per hour and higher, we did see galloping on several of our transmission lines and had momentary outages across the system,” Peterson said, referring to transmission lines bouncing or “galloping” in high winds. Momentary outages are those that last one minute or less.
“All told, there were 120,000 consumer outages with 948,00 consumer outage minutes between momentary and sustained outages,” Peterson said.
Great River Energy’s Lakefield Junction Station power plant also lost power during the storm.
“We lost all station service power as a result of storm damage to a structure on the 345-kilovolt transmission line feeding the station,” said Preston Walsh, leader of combustion turbines at Great River Energy.
The plant’s emergency diesel generator failed as well, leaving the plant without heat and electricity during the blizzard.
“More than 30 employees responded to the emergency restoration efforts to safely integrate temporary generators into the facility over the Christmas holiday weekend,” said Great River Energy Vice President and Chief Power Supply Officer Jon Brekke. “This was a tremendous effort and response from many to prevent damage to Lakefield’s critical systems during these freezing conditions. We are grateful for our employees’ efforts.”