The North Carolina Waste Awareness & Reduction Network filed its objection with the state Utilities Commission. The group said Charlotte-based Duke Energy would sell electricity resulting either from energy efficiency programs or construction of new power plants financed by ratepayers.
Company spokeswoman Paige Sheehan said it needs to modernize power plants and prepare for growing demand.
Duke Energy announced it would supply the electrical cooperatives just days after South Carolina's state-owned utility dropped plans for a $1.25 billion coal-fired power in August. The co-ops were served by Santee Cooper.