Xcel exploring how to fix issues that caused outages during polar vortex

Xcel Energy will "revisit" its planning for extreme cold weather after the utility's natural gas system proved faulty during January's big freeze.

The problems led to outages for about 180 customers and prompted nervous Xcel executives to ask all of the company's 460,000 gas customers in Minnesota to lower their thermostats to 63 degrees to conserve gas supplies.

The problems were discussed at a hearing Thursday called by state utility regulators to review energy providers' performance from Jan 28 through Feb. 1, when Minnesota faced temperatures of 30 below and beyond.

"Overall, it would appear the state's utilities [both gas and electric] performed remarkably well, but there were some challenges," said Dan Lipschultz, vice chairman of the Minnesota Public Utilities Commission (PUC).

Within Xcel's distribution system, natural gas pressure got so low that in the Princeton area, 152 customers lost gas service for a day, while another 29 in Hugo also lost heat for a shorter time.

Fearing that the low pressure in its system could cause further outages in six surrounding communities, Xcel asked residents there to turn their thermostats down to 63 degrees.

Then, "out of an abundance of caution," Xcel extended that request to all its Minnesota gas customers, said Eric Kirkpatrick, Xcel's associate vice president of gas operations.

The low pressure was caused by a record spike in demand. With temperatures dropping to 20 to 30 below, "every house has the furnace going almost all of the time," Kirkpatrick said. The demand was essentially higher than Minneapolis-based Xcel had planned for in its cold-weather modeling.

"Our system design wasn't adequate for the loads we actually saw," Kirkpatrick said. The company will now "revisit the design model for our gas system."

Xcel, Minnesota's second largest natural gas provider, will be reinforcing its gas distribution system in areas that lost service during the arctic blast, he said. That means increasing the number of gas lines or swapping smaller pipes for bigger ones.

CenterPoint Energy, Minnesota's largest gas utility with about 870,000 customers, also saw low pressure in its system, as did other Minnesota gas providers. But none of their customers saw outages.

The PUC also heard from Xcel, the state's largest electricity provider, on power challenges caused by the freeze, as well as from Duluth-based Minnesota Power and Fergus Falls-based Otter Tail Power. While there were some electricity outages during the deep freeze, problems weren't of the magnitude of Xcel's gas shortage.

However, most wind turbines in the state shut down when temperatures sunk to 20 to 25 degrees below zero, utility executives said. The wind turbine issue also was discussed at length Wednesday at a meeting of the Midcontinent Independent System Operator, or MISO, which runs the grid in Minnesota and parts of 15 other states.

When temperatures falls as low as they did in January, wind turbines are programmed to stop so they don't suffer mechanical damage.

Mike Hughlett • 612-673-7003