Sodium bicarbonate is used for dry flue gas treatment to bind acidic reacting flue gas components such as sulfur oxides or hydrogen chloride. Competing processes include washing methods and conditioned dry methods based on lime adsorbents (especially Ca(OH)2). Considering energy efficiency, effort of retrofitting, operation and handling, as well as residue management, sodium bicarbonate shows significant advantages. This study examines two retrofitted waste-to-energy plants which utilized both sodium bicarbonate and lime hydrate.