You don’t throw your keys to a perfect stranger and let him take the family SUV for a spin — no matter how careful he promises to be. Yet, some 22,000 presumably level-headed Colorado ratepayers turned over control of their household thermostats to the state’s largest public utility, Xcel Energy.

What could go wrong? Last week’s heat wave, for one thing.

As reported by The Gazette, Xcel Energy acknowledges it remotely adjusted those customers’ internet-connected thermostats last Tuesday due to high temperatures and an unexpected loss of generation. It was the first time Xcel took over thermostats in the six-year history of its voluntary “AC Rewards” program to reduce electrical loads on the power grid.

Customers with “smart,” wifi-ready thermostats can sign up and get cash incentives to participate. Presumably, Xcel’s sales pitch doesn’t emphasize the possibility of sweltering inside your own home as temperatures rise outside.

Xcel isn’t the only public utility to entice customers into relinquishing control of their household creature comforts. Colorado Springs Utilities, the municipally owned behemoth serving the state’s No. 2 metro area, similarly offers ratepayers who have wifi-connected thermostats a $50 bill credit for enrolling in its Peak Energy Rewards program. Customers who stay enrolled get another $25 bill credit each year. The utility’s website exhorts customers, “Let’s work together to help reduce our energy use during peak demand times.”

Last week’s episode involving Xcel was eerily reminiscent of the classic sci-fi film, “2001: A Space Odyssey” — in which a spacecraft’s onboard computer turns against its crew and takes control of the ship. The fact that Xcel’s “AC Rewards,” in some circumstances, won’t even let participating customers override and use their air conditioning must have left them wanting to emulate Discovery One’s lone surviving astronaut, who finally disabled rogue computer “HAL.”

An Xcel spokeswoman pointed out to The Gazette that customers always can opt out. And some may do just that — now that the misery has been inflicted.

How things have changed. It all used to be pretty simple: The power company charged ratepayers for the kilowatt-hours they consumed. The more ratepayers used, the more money the power company made.

Nowadays, those same public utilities are leading the crusade for energy conservation. They are installing not only smart thermostats but also smart wifi meters on ratepayers’ homes. The next-generation meters let utilities like Xcel monitor household use and charge more for electricity during peak-use periods — unless ratepayers opt out of that, too.

Why are energy providers putting the squeeze on energy consumers? Because public utilities aren’t really private-sector players in a free market. Some, like in Colorado Springs, are run by local government while others, like Xcel are owned by stockholders but heavily regulated by the state. And all of them function as monopolies.

Hence, public utilities’ basic business decisions — such as their growing reliance on renewable energy as well as how much they can charge for it — are dictated by government regulators. Which means state and local government’s policy priorities and initiatives have become the utilities’ policy priorities and initiatives.

That’s not to say government wants to set your thermostat just because your utility offers to do so. Not yet, at any rate. But you have to wonder what it all bodes for the future.