Consumer advocates typically don't favor surcharges.
They "can create a system that fails to match expenses with corresponding revenues," said Angela Speir Phelps, a former Georgia PSC commissioner. Phelps now works as senior director for Georgia Watch, a consumer advocacy group in the state.
Utilities maintain that the surcharge provides cost and revenue certainty.
Consumer advocates say surcharges can lead to overcharges, and to excessive earnings for the utility. Surcharges like that proposed by AGL insulate some company revenues from the PSC's strictest scrutiny, they say.
The cost of projects like AGL's should be rolled into the company's general rates, which get more detailed oversight, they add. The PSC staff reviews rates to make sure a monopoly utility's earnings don't get out of line.
AGL said that, according to a report by the American Gas Association, 22 utilities in 11 states already have infrastructure surcharges, or they have them pending.
AGL President Suzanne Sitherwood said it's a good time to undertake the project because the cost to borrow and the cost of construction are both relatively low.
She said with commodity rates for natural gas lower lately, "the overall impact on customers may be largely offset."