LINCOLN, Neb. (AP) — The Nebraska Supreme Court has ruled that Nebraska’s largest public power utility must open its books and disclose the expense of generating electricity from its individual power plants.

The decision Friday came in the case of an open records lawsuit against Nebraska Public Power District brought by Lincoln-based energy firm Aksamit Resource Management. Aksamit is a private company that seeks to compete with NPPD.

NPPD had refused Aksamit’s repeated requests for the information, arguing that doing so amounted to revealing trade secrets. A district court agreed with the larger utility, and Aksamit appealed.

But the Nebraska Supreme Court overruled the lower court’s finding, saying a public entity must show that there is no public purpose served by releasing records it wants to keep from public view. The high court says NPPD failed to show that.