A universal innovative burner with vertical feeding of fuel was developed. The burner allows for installation in coal-fired boilers of various manufacturers and to meet the requirements related to emission limits and thermal efficiency. The paper presents the results of thermal and emission tests after the application of innovative construction solutions of the retort burner in a water boiler using eco-pea coal and alternative fuel produced in the form of pellets from fine coal and coal sludge. Obtained results were applied to current requirements related to emissivity and thermal efficiency for boilers with automatic fuel hoppers equipped with a retort burner. Combustion in the developed innovative retort burner for eco-coal and alternative fuel pellets allowed compliance with the highest emission classes for gas and dust substances as well as high combustion efficiency.