The Public Utilities Commission ordered Xcel Energy to study the cost of new pollution control equipment at two of its coal-burning units in Sherburne County and compare that with the cost of replacing them with a cleaner alternative. Environmental groups consider the order a victory, but Xcel says it was planning something similar. The study is due next summer.

A solar energy program that has provided rebates to more than 500 Xcel Energy customers in Minnesota since 2010 will be phased out starting in 2013. The Minneapolis-based company said its Solar Rewards program met its goal of adding six megawatts of solar-powered electricity to its system, and now it wants to devote more of its efforts to energy conservation.

Minnesota Power says it wants to further study the environmental benefits and economic impacts. The Department of Commerce recommends closing at least three of utility's coal-burning plants by 2016. Each unit is more than 50 years old. Environmental groups have also urged closing the coal power plants, while industrial users want state regulators to disregard the advice.

The Minneapolis-based utility announced Thursday a nine-year plan to invest in changes to their Minnesota power plants in preparation for new federal regulations.

A consortium of six North Dakota utilities and coal mining companies is chipping in $500,000 to fight Minnesota's ban on energy generated by burning coal. The state's Industrial Commission filed the original lawsuit. The North Dakota legislature is also committing funds for the legal challenge.