ATLANTA --- Georgia prison officials are concerned they could run out of ways to save money before the state budget stops shrinking.

First the Department of Corrections closed prisons and housed three inmates in cells built for two. Now the agency is turning out lights in its 2,200 buildings and finding other ways to save on its energy bills, thanks to $16.5 million in federal stimulus grants won in the spring.

With half the grant money, the agency will install meters that report to a central office if electricity usage rises above predicted levels so unneeded lights or other equipment can be immediately turned off. The other half will go to inspecting every building to make sure all the equipment works in sync, said Larry Latimer, the director of engineering and construction.

"You'd be surprised how often someone reversed the wires on a fan and the blades are turning the wrong way," he told the agency's board Thursday.

He anticipates savings of $4 million yearly, based on similar efforts in Missouri's prison system.

The department is also working with the Board of Pardons and Paroles on streamlining screening that could lead to reprieves for medical reasons. Releasing chronically ill inmates saves the department heavy medical costs.

All the efforts still might not be enough, board members said. State tax collections have continued to slump, forcing the agency to deal with a growing inmate population and a budget 10 percent -- or $100 million -- less than its peak.

And $97 million in federal "stabilization funding" runs out after next year.

Corrections Board member Jim Whitehead of Augusta said he expects more cuts after meeting recently with Rep. Ben Harbin, R-Evans, who leads the House Appropriations Committee.

Corrections Commissioner Brian Owens said the state was already withholding 5 percent of each month's appropriations -- as it is this fiscal year for all agencies -- but the withholding was reduced to 2 percent once projections showed a severe cash-flow problem for Corrections.