Xcel Energy says it remotely adjusted internet-connected thermostats Tuesday because of high temperatures and an unexpected loss of generation.

This was the first time Xcel activated control of about 22,000 customers’ thermostats in the six-year history of its voluntary AC Rewards program to reduce electrical loads on the power grid, Xcel spokesperson Michelle Aguayo said in a statement.

Customers who have approved internet-connected thermostats can sign up for the program and receive cash incentives to participate. 

Sierra Club, environmental groups petition EPA to ban natural gas for home heating

The program typically allows customers to override and continue to use their air conditioning, but in certain situations, they are not able to do so.

“Customers are aware of this when they enroll in the program,” said Aguyao, who stressed that this is a voluntary program and that customers are free to opt-out if the program “no longer meets their needs.”

No information on the nature of the power shortage was available at press time.

Colorado legislators embrace electric vehicles and mileage reimbursements