Georgia Power spokesman Mark Williams says a plan to shut down 15 generating units would result in the closure of three power plants across the state.

Georgia Power announced Monday that it will request the state's public service commission to approve decertifying and retiring units at plants in Putnam, Coweta, Glynn and Chatham counties.

"We recognize the significant impact that it's going to make but we have to make decisions that are in the best economic interest of our customers," Williams told WGXA in a phone interview.

Williams says shutting down the units would result in the complete retirement of all the facilities except for Plant Yates, in Coweta County.

The company says several factors, including economic conditions and costs to comply with environmental regulations, contributed to the decision.

The plant shutting down in Putnam County means a loss of more than $3 million dollars from the county's annual budget of $17 million.

"We can try to cut down and reduce our expenses and try and bring that number in line but the numbers is too great at this time to say for certain that it wouldn't necessarily mean an increase in property taxes sometime in the future," Putnam County Manager Paul Van Haute said.

Van Haute says he and the commissioners knew this day was coming but wanted the Public Service Commission to force Georgia Power to make the modifications to keep the unit’s operating.

"Unfortunately the EPA has legislated coal fire plants out of existence and this is the casualty that will affect the county," Van Haute said.

Williams says 480 employees will be impacted, and they'll be offered opportunities to retire or look for a new position within the company.

The company plans to shutter the units by April 16, 2015.