Democrats Anna Tovar and Bill Mundell lead the field of six candidates vying for three seats on the Arizona Corporation Commission, on Tuesday night with 79 percent of precincts reporting.
A third Democrat, Shea Stanfield held third place for most of the election evening until Republican Incumbent Lea Marquez Peterson and Republican Jim O'Connor pulled ahead of her.
Republican Eric Sloan remained in the sixth spot throughout the evening.
Three Republicans and three Democrats are on the ballot in a race that could change the commission's political makeup, which regulates investor-owned and private electric, water, and gas utilities in Arizona.
Republicans hold a 4-1 advantage on the Commission which is currently in the process of updating energy rules that will determine how much renewable and solar energy is used by utilities.
If Democrats win at least two seats, the balance of power would shift away from Republicans for the first time in at least a decade.
Tovar, Mundell, and Stanfield all ran on a platform of boosting residential solar use and implementing requirements for utilities to use more solar energy.
Marquez-Peterson, O'Connor and Sloan all oppose renewable energy mandates.