Three electric space heaters were running at our house the whole weekend of Valentine's Day, when it dropped to 19 below zero here in the Twin Cities. And while our furnace is fueled by natural gas, it won't fire up without electricity.

When blackouts and other trouble happened over the following week in Texas, it felt like good fortune to live in a state where the power stays on.

It's remarkable, really, that millions could go without power in a country as wealthy as ours, as they did in Texas. The consequences were deadly.

Texas Gov. Greg Abbott at first blamed frozen wind turbines. While obviously wrong, Abbott's claim did get people wondering about the reliability of electricity as the country replaces fossil-fuel generation with wind, solar and other renewable sources.

Some wind turbines in Texas did stop spinning in the cold snap. They do here, too, although the winterized versions in the northern plains are typically good down to 22 below before they shut down.

Minnesota's power companies, though, don't really count on wind turbines to contribute much during cold snaps, but that's not because they shut down. Instead, it's because the wind rarely blows enough to generate power when the temperature gets that cold. The companies already factor that into their plans for generating power in extreme conditions.

Power-company executives in this region told me cold snaps can be rough on equipment and the people who have to go outside to keep it working. But they said, it's Minnesota, it gets cold.

Their first explanation for why our system held up so well is that it's what the regulators here require.

That's not meant to be funny. It just means that the business is structured around capacity and the providers agree to make sure the state's consumers always have power.

This industry has been regulated since not long after it got going. To deal with local monopolies, governments began to cap the rate of return on electric utilities' capital.

If capital spending is allowed to generate a return, though, power companies have plenty of incentive to just keep spending. The check on that is the regulator, weighing in on whether it's appropriate spending.

You see this tension in Minnesota all the time, like when Xcel Energy sought approval to recover hundreds of millions of dollars of cost overruns from customers for upgrades at its nuclear power station in Monticello.

But that basic regulatory framework is what Texas officials decided to scrap. Competition from other providers will keep power companies from wasteful spending, the Texans calculated.

Instead of requiring utilities to meet a certain capacity, the Texas lawmakers reasoned that utilities would have the incentive to provide the capacity because they could expect higher prices during periods of peak demand for energy.

Minnesota power-company executives, such as Jon Brekke of Maple Grove-based Great River Energy, think this was shortsighted.

To them it looks like the industry in Texas didn't see how to get a return for winterizing equipment or having much excess capacity. Demand peaks in Texas when it's hot, and that's when natural gas to burn to generate electricity is plentiful and no one has to worry about any equipment freezing.

That state is still sorting out all the reasons for the failures that arose when cold weather arrived, but the upshot is lots of generating capacity in Texas went offline.

Here in Minnesota, as in Texas, some wind turbines did shut down for Xcel Energy, said Chris Clark, the company's president for our region — pretty much as expected.

Still, the cold weather was both longer lasting than originally forecast and extended farther south, among other things straining natural gas supplies. That's one reason why Xcel keeps a supply of fuel oil on hand for its natural gas-fired plants.

Great River Energy, a co-op that serves other electric co-ops, does the same thing at its gas plants, said Brekke, who is its chief power-supply officer. From a cold start, some of its natural gas units can start generating electricity within minutes.

Turning to backup plans also explains why Xcel decided, after hearing the weather forecast earlier this month, that it would fire up the Allen S. King plant on the St. Croix River east of St. Paul.

This big coal-fired plant, built more than a half-century ago, is being maintained to run only when it's really needed. Clark said it hadn't been used much since the hot weather of last August.

The King plant is scheduled to be shut down for good later this decade, which illustrates a point Brekke made.

Our region has been quickly moving from coal-fired power to renewables and natural gas. In 10 years ending in 2019, natural gas' share of total Minnesota power generation more than tripled, renewables' share almost doubled and coal slipped from 56% of power generation to just 31%.

The worrisome season these days at Great River isn't the summer anymore but the winter, Brekke said, when there's stiff competition for natural gas supplies. Gas is cheap and readily available in the summer.

The power industry seems to know how it can reach an 80% reduction in carbon emissions, which Xcel has pledged to do by 2030.

"But we have also proposed getting to 100% carbon free by 2050," Clark said. "And one of the reasons we chose that 2050 date is knowing we need some technology and innovation to solve that last 20% of carbon reduction."

For now, Xcel sees carbon-emitting natural gas plants being part of its generation plans in Minnesota after its coal plants have been retired.

To get to 100% carbon free, natural gas plants can perhaps be modified to run on a different fuel, Clark said, or an effective way to trap their carbon may emerge. More effective ways to store energy generated from renewable sources may also develop.

Clark said the transition to carbon-free may go faster, but none of this sounds easy.

"If you think about a polar vortex, and the one we just had was 10 days long or so, there isn't a storage resource out there that can carry you through 10 days," Brekke said. "And there may never be one that's cost-effective." 612-673-4302