OLYMPIA - State and federal governments signed off Wednesday on a long-sought plan to partially restore the site of two unfinished nuclear power plants north of Richland.

Gov. Gary Locke called it a "historic agreement that ties up some loose ends of the old supply system story."

"This is a win for everybody," said Vic Parrish, chief executive of Energy Northwest, formerly known as the Washington Public Power Supply System.

The consortium of public utilities began building five nuclear plants in the 1970s but completed only one of them, the Columbia Generating Station at Hanford. Two of the remaining four, both in Grays Harbor County, have been turned over to a local redevelopment authority.

Jim Luce, chairman of the state's Energy Facility Site Evaluation Council, said that could have cost as much as $115 million.

Instead, the state agreed to allow the plants to be only partially demolished and sealed up at a cost of $45 million.

Bonneville has agreed to become financially responsible for both plants.

Though work to clear the sites of the most immediate health and safety hazards already has begun, heavy demolition work won't begin for at least 23 years and must be finished by 2029.

In return for the delay, BPA will put up $3.5 million, which the siting council and environmental groups will use to buy up privately owned land to preserve shrub-steppe habitat in and around Benton County.

Len Barson, government relations director for the Nature Conservancy of Washington, said that's a good tradeoff for not returning the nuclear site to its original condition.

The siting council expects to try to use the money to leverage state and federal matching dollars.

Barson believes as much as 10,000 acres of shrub-steppe habitat could be purchased for preservation, though other kinds of environmental upgrades also will be considered.

Luce said he originally sought to have the site completely restored but later agreed it didn't make sense given the cost.

"We could force the issue but it was not reasonable under the circumstances," he said.