Salt River Project is about to start a three-week test burn of 3,900 tons of forest debris at its Coronado Generating Station (CGS) near St. Johns.

The test burn helps evaluate the viability of reducing fire risk in Arizona’s fire-prone watersheds while using the collected debris, biomass, as a renewable source of power.

The first test burn will be Wednesday at CGS Unit 1 to evaluate the power plant’s coal-handling system’s ability to burn wood or biomass. If successful, a full test will be held in early November, burning 2 percent biomass in the mixture for 10 days. The testing will continue with another 10-day burn using 5 percent biomass.

The test burn program is a first for Arizona, burning forest debris together with coal. CGS is designed specifically for coal. The testing does not require permanent modifications to the power plant and will help identify cost-effective solutions and potential impacts for burning biomass.

In the forest-restoration process, trees are harvested to reduce the risk of fire, resulting in biomass that has little reuse value. Traditionally, this type of biomass is burned in piles, resulting in smoke and emissions.