MADISON, Wis. — Wisconsin regulators properly approved a Madison-based utility’s plan to build the Bent Tree Wind Farm, the state Supreme Court ruled Wednesday.

The Citizens Utility Board and the Wisconsin Industrial Energy Group contended the Wisconsin Public Service Commission approved Wisconsin Power & Light’s plan to build a massive wind farm north of Albert Lea under the wrong statutes. The groups argued the PSC improperly approved the farm under a so-called certificate of authority rather than a certificate of public convenience, which would have required a more stringent review.

The Supreme voted 5-2 to uphold a Madison’s judge’s finding that the farm was properly approved. Justice Patience Roggensack wrote in the majority opinion that the PSC’s conclusion — that a public convenience certificate applies only to projects within Wisconsin — was reasonable.

Roggensack said the court must give due consideration to the PSC’s decision, saying the commission took comments from interested parties and weighed them against its own extensive experience in reviewing utilities’ construction applications.

The consumer group’s attorney, Kira Loehr, didn’t immediately return a message.

When the PSC approved the farm, the project was expected to cost about $500 million. WP&L hoped to recover the costs through a $91.7

The Bent Tree farm was expected to cost about $500 million. WP&L planned to recover the costs through a $91.7 million electric and natural gas rate increase, which broke down to about $9 more per month for electricity and $2.40 more per month for gas for a typical residential customer. About a third of that increase would go toward the wind farm.

Neither Kira Loehr, the consumer groups’ attorney, nor Steve Schultz, a spokesman for Alliant Energy, WP&L’s parent company, immediately responded to phone messages Wednesday seeking comment.

PSC spokesman Matt Pagel said he had no immediate comment.