North Dakota officials are blaming a Minnesota law for unfairly holding back development of new coal-burning power plants that would export electricity across state lines.

But Minnesota says worries about "alleged lost sales" by coal-burning utilities in North Dakota "all hinge on speculation and contingent future events" — and that the law is a legitimate way to cope with looming greenhouse gas regulation.

Attorneys for the two states set the battle lines this week in a 22-month-old lawsuit filed by the state of North Dakota and its coal and utility interests. The suit seeks to overturn the 2007 Minnesota Next Generation Energy Act (NGEA) — signed by then-Gov. Tim Pawlenty — that bans new Minnesota coal power plants as well as imports of new coal-based electricity from other states.

In motions for summary judgment filed Thursday, each state argued that the other is wrong.

"Minnesota has willfully exceeded the bounds of permissible regulation by exporting its policy agenda and imposing regulation on a multistate region, all in a misguided effort to reduce carbon emissions from electricity generated ... outside Minnesota," said the North Dakota interests' attorneys in their motion for summary judgment.

The lawyers for North Dakota said the Minnesota law is impeding development of new coal power plants near Gillette, Wyo.; Selby, S.D., and South Heart, N.D.

"On its face, the NGEA clearly and expressly discriminates against electricity generated by coal," they wrote.

Minnesota's defense

The Minnesota law, which also requires utilities to promote conservation and develop renewable energy, bans coal power plants because they are a leading source of greenhouse gases linked to global warming. Defending the law, attorneys from the Minnesota attorney general's office argued that Minnesota tried to get out ahead of anticipated federal regulation of carbon-dioxide emissions. States have long regulated utilities, and this is another case of it, they argued in court papers.

North Dakota, which has coal deposits and relies heavily on them for power generation, contends the Minnesota statute violates the U.S. Constitution's "commerce clause" that bars states from unfairly interfering in interstate commerce. The suit also contends that other federal laws trump Minnesota's statute.

Attorneys will argue in person next month before U.S. District Judge Susan Richard Nelson, who will decide what, if any, parts of the case would go to trial.

Until now, much of the work on the case has been done behind the scenes by a swarm of lawyers. According to the court docket, 30 lawyers are listed as having participated in the case now or in the past. Eight attorneys representing seven environmental groups tried to join in to help defend Minnesota, but a judge concluded last December that the attorney general's office could handle the lawsuit itself.

The lawsuit was brought by the state of North Dakota, two coal companies, their trade association and three electric cooperatives based in that state. The defendants are the Minnesota public utilities commissioners and the state commerce commissioner.