Industry experts say the challenger has his facts wrong.
Oppenheimer made the charge Sunday in a televised debate and again Monday in a conference call with reporters.
"This is unacceptable, and a clear neglect of responsibility on the part of incumbent commissioner Chuck Eaton, who publicly criticized the former incumbent for natural-gas prices that were just 25 percent higher than the national average when he ran for office in 2006," Oppenheimer said. "Eaton has clearly turned his back on the families of Georgia by not ensuring the retail price they are paying for natural gas reflects the dramatic plunge in wholesale pricing the rest of the country is enjoying."
The Democrat draws from charts compiled by the U.S. Energy Information Administration that compares the delivered cost of residential natural gas in each state. During the most recent four months for which data is displayed, Georgia's rates are higher than all but the island state of Hawaii.
Angelina LaRose, team leader in EIA's Office of Petroleum, Natural Gas & Biofuels Analysis, said, "It may be that a combination of fixed charges and low consumption that is making the prices look particularly high."
In Georgia, delivery charges remain the same year round even though customers may only use gas a few months of the year. So in the four summer months Oppenheimer pointed to, the pipeline costs were spread over fewer units of gas.
Other states pass along those distribution charges just when the gas is used, making them higher than Georgia in the winter, according to Kevin Greiner, CEO of Gas South, one of the state's licensed marketers.
"You've got to be very careful looking at month-to-month comparisons," he said.
Another factor in the federal figures is that they include gas sold by dozens of cities that aren't regulated by the Public Service Commission, notes a memo from Atlanta Gas Light Co. The EIA also doesn't include the value of gift cards, cash back, Delta Air Lines SkyMiles and other offers from the competing marketers in Georgia.
Atlanta Gas' own calculations show fixed-rate plans in Georgia on a 12-month basis were lower than the average for the Southeast.
Eaton issued a denial of Oppenheimer's claims, adding that the commission does regularly monitor the natural-gas market place.
"Natural gas rates in Georgia are below the national average, period," he said. "The Public Service Commission and our staff review natural gas prices in Georgia on a continuous basis, and the rates paid by Georgia consumers for natural gas remain below the national average, and competitive with neighboring states."