PIERRE, S.D. (AP) — State regulators on Tuesday approved an agreement to refund roughly $10.9 million to the thousands of Xcel Energy customers in South Dakota as a result of last year's federal tax cuts.

The South Dakota Public Utilities Commission voted for the settlement, which also bars increases in base electric rates for the company's South Dakota customers until at least 2021. Public Utilities Commission Chairwoman Kristie Fiegen said the tax cuts mean rate stability and a refund for consumers.

Minneapolis-based Xcel Energy has more than 93,000 customers in South Dakota. Xcel Energy-South Dakota president Chris Clark said in a statement that the company is pleased to deliver benefits from the tax overhaul to its South Dakota customers.

The company estimates the average refund for a residential consumer will be about $56, but the number will depend on actual usage.

"The savings from the tax cut will also enable us to continue investing in important projects for the future — projects that result in better levels of service for customers and provide the benefits of a modern electric system at a lower price," Clark said.

A Public Utilities Commission spokeswoman said in an email it's anticipated that additional such proceedings will be held for other utilities that serve South Dakota.