Electricity generation from coal is one of the leading contributors to greenhouse gas emissions in the U.S. and has adverse effects on the environment. Biomass from forest residue can be co-fired with coal to reduce the impact of fossil-fuel power plants on the environment. W. A. Parish power plant (WAP, Richmond, TX, USA) located in the greater Houston area is the largest coal and natural gas-based power generation facility in Texas and is the subject of the current study. A life cycle assessment (LCA) study was performed with SimaPro® and IMPACT 2002+ method, for the replacement of 5%, 10%, and 15% coal (energy-basis) with forest residue at the WAP power plant in Texas. Results from the LCA study indicate that life cycle air emissions of CO2, CO, SO2, PM2.5, NOX, and VOC could reduce by 13.5%, 6.4%, 9.5%, 9.2%, 11.6%, and 7.7% respectively when 15% of coal is replaced with forest residue. Potential life cycle impact decreased across 9 mid-point impact categories of, human/aquatic toxicity, respiratory organics/inorganics, global warming, non-renewable energy, mineral extraction, aquatic acidification, and terrestrial acidification/nitrification. The potential impact across damage/end-point categories of human health, ecosystem quality, climate change, and resources reduced by 8.7%, 3.8%, 13.2%, and 14.8% respectively for 15% co-firing ratio.