Power outages triggered by once-in-a-lifetime winter weather in southern states crept to the corners of western Minnesota this week.

A stretch of rural southwest Minnesota and the city of Moorhead in the northwest — unlike most of Minnesota — are part of a regional electrical grid that travels through the Dakotas south to the edges of Texas.

As record low temperatures, complicated by severe snow and ice storms, hit states such as Texas, Oklahoma and Arkansas, that grid — called the Southwest Power Pool — did not have enough electricity as coal and natural gas plants, as well as wind turbines, could not keep up with customers' needs.

Investigations into why that happened are starting, but customers in Tyler, Lake Benton and Ivanhoe in southwest Minnesota and the city of Moorhead in the northwest felt the results.

Minnesota's Lyon-Lincoln Electric Co-op got word Tuesday morning that power would be cut to about 2,000 customers in its territory. The blackout started around 7 a.m. and lasted just over an hour.

In Moorhead, the city's municipal utility received the same order from grid operators, and about 9,800 customers lost power for about half an hour Tuesday morning.

"I can't recall that ever happening," said Travis Schmidt, general manager of Moorhead Public Service. "It's never even been a thought."

The Southwest Power Pool (SPP), based in Little Rock, Ark., is a regional transmission operator that runs the grid in parts of 14 central states from North Dakota down to the Texas Panhandle.

A few other western Minnesota retail electric co-ops are part of the SPP, though it doesn't appear they were hit with outages.

Most of Minnesota is part of another regional grid called the Midcontinent Independent System Operator (MISO), which is based in Indiana and has an operations center in Eagan. MISO, which includes parts of 15 states and Manitoba, is adjacent to SPP on the east.

Like SPP, MISO has a lot of turf in the south — including parts of Arkansas, Louisiana and a sliver of Texas — and did institute some rolling blackouts. But MISO's north section, including the Upper Midwest, appeared to hold firm.

North America has nine grid operators, dubbed either regional or independent grid operators — RTOs and ISOs in electric speak. The grid operators are nonprofits whose members include utilities and other entities involved in power transmission, marketing and generation.

The Electric Reliability Council of Texas, or ERCOT, is the grid operator for most of Texas, and it is presiding over a massive failure that left most of the state without power for hours or days.

Texas' grid operators told the Associated Press on Friday that the system has returned to normal for the first time, though smaller outages remain.

The storm so far has claimed 59 lives, the AP said.

SPP encountered some of the same issues as ERCOT did.

"You had the disastrous combination of low wind, low natural gas, record low temperatures and record high electricity demand," said Chris Studer, spokesman for South Dakota-based East River Electric, which supplies power to co-ops in its home state and western Minnesota, including Lyon-Lincoln.

East River is itself a co-op that owns transmission equipment and buys electricity from North Dakota-based Basin Electric Power Cooperative and the Western Area Power Administration, which markets electricity produced by federal dams.

Within this maze, when the Southwest Power Pool declared a "Level 3" emergency event early Tuesday morning, everybody scrambled. Power demand was exceeding supply, so the last resort was implemented: rolling blackouts across SPP's entire grid.

"The rolling blackouts are necessary to save the power grid," Lyon-Lincoln told customers on its Facebook page. "This was an absolute necessity in order to avoid much longer, more sustained outages."

Tim O'Leary, Lyon-Lincoln's general manager, said one transmission substation that serves his customers was chosen "randomly" by the grid operator as part of the larger regional rolling blackout.

He said he did not know of other co-ops in Minnesota hit with the temporary power loss.

As for MISO, this week it declared a "Max Gen Event" for its southern region, meaning the grid was facing a generating capacity emergency.

MISO also declared such an emergency in late January 2019 when a severe freeze pushed the Upper Midwest's electricity grid to the limit.

With temperatures falling to 30 below, both coal-fired and gas-fired power plants appeared to have some mechanical problems. Wind turbines shut down as temperatures dropped below the limit at which they can operate without being damaged.

About 25% of the region's electricity-generation fleet was unavailable because of forced outages, MISO said at the time. Some utility-level issues were exacerbated by the weather, but the electric grid held up.

Mike Hughlett • 612-673-7003