ATLANTA — Analysts with the Georgia Public Service Commission warn that Georgia Power’s proposed expansion to support new data centers could raise residential bills by $20 or more per month.

The PSC staff recommends approving only about a third of the 10,000-megawatts of new generation Georgia Power is seeking, saying most of the request isn’t backed by firm contracts and could leave customers paying for unused infrastructure.

They also report that Georgia Power’s demand forecast may be overly optimistic, posing a risk that the company will build more capacity than is actually needed.

Georgia Power officials dispute the notion that the demand is speculative.

The warning comes weeks after two incumbent commissioners lost reelection bids amid voter frustration over rising utility costs.

The commission is set to vote on the plan December 19.