A joint Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) report presents the results of an evaluation funded by the Bioenergy Technologies Office that examines the effects of substituting up to 20% renewable biomass for coal in electricity production. This report is the first publically available assessment of its kind to investigate the impacts of co-firing biomass with coal at concentrations greater than 10% biomass without modification to the pulverized coal plant or its feed system. Findings have expanded the methodology that communities and energy providers can use to evaluate the potential economic and environmental benefits of using biomass in their coal plants. The research examined two case studies—one using woody biomass in central Alabama and the other using switchgrass in the Ohio River Valley—for blending a relatively high volume of torrefied biomass with ground coal in pulverized coal power plants. Under both scenarios, researchers found that substituting 20% renewable biomass for coal has the potential to reduce the life-cycle CO2 emissions of the power plant, a finding aligned with the President’s Climate Action Plan to cut carbon pollution from U.S. power plants.  Results of the research are consistent with a 2012 National Energy Technology Laboratory co-firing study that examined the greenhouse gas reduction benefits of biomass co-firing, as well as the cost of the electricity produced. The evaluation found that other factors are also important when considering the use of biomass in pulverized coal plants, such as the cost of the biomass feedstock and the distance of biomass collection sites. The U.S. Department of Energy’s Bioenergy Technologies Office is focused on forming cost-share partnerships to develop, demonstrate, and deploy technologies for advanced biofuels production. Although the Office’s biopower funding closed out with fiscal year 2014, the results of this and other funded research can be helpful to communities, especially in the southeastern United States, that are involved in biopower production.