BECKER, Minn. (AP) - State regulators have ordered Xcel Energy to study the efficiency of its two oldest coal-fired plants.

A report from the Minneapolis utility on long-term options for the Sherco Generation Station is due by July. Xcel will study whether spending millions of dollars for additional pollution controls is worth the expense.

The coal-fired plants, near Becker, were built in the 1970s and are part of the backbone of the utility's electricity generating capacity in the Upper Midwest.

Environmentalists would like to see the units shut down and replaced with cleaner power. Kevin Reuther from the Minnesota Center for Environmental Advocacy, says there are many options that are more "environmentally friendly" and a better long-term option for ratepayers.

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