OMAHA, Neb. (AP) _ Five western Nebraska public power providers are suing a Colorado-based power cooperative, accusing the co-op of grossly overcharging its Nebraska members for electricity.

The five Nebraska providers also say that Tri-State Generation and Transmission Association Inc., as well as its president and several board members, are holding the Nebraska members captive by demanding they pay $220 million to buy out their Tri-State contracts.

The Nebraska utilities, based in Alliance, Bayard, Grant, Hay Springs and Mitchell, filed their lawsuit Monday in U.S. District Court in North Platte.

Bringing the suit are PREMA...Pandhandle Rural Electric Membership Association...in Alliance, Northwest Rural Public Power District in Hay Springs, Bayard's Chimney Rock PPD, Roosevelt PPD in Mitchell, and Midwest Electric Cooperative in Grant.

They ask the court to find, among other things, that Tri-State breached its contracts with the utilities. They seek unspecified damages and all court and attorneys' fees.