Piedmont Natural Gas customers in the Carolinas will see lower rates starting next month after regulators approved a cut in the utility's benchmark price for fuel. Utility regulators in North Carolina and South Carolina have approved Piedmont Natural Gas' proposal to reduce the fuel portion of customer rates, effective Jan. 1. The N.C. Utilities Commission voted this week to allow Charlotte-based Piedmont to cut its benchmark rate for natural gas prices to $4 per dekatherm from $4.75 .