Most appliances for energy grain are found on farms and are between 15-30 kW. A continued increase of use of energy grain and similar fuels are expected also in appliances somewhat larger. Back draws are high ash content and high content of sulphur and chlorine compared to wood based fuels. Sulphur is during combustion formed into sulphur dioxide that can form sulphuric acid, and chlorine forms hydrochloric acid. Severe corrosion damages have been reported when these acids are allowed to condense. Corrosion has also been noticed in on roofs etc and the species contribute to acidification of the environment. To avoid corrosion during combustion of grain it is recommended to keep the temperature high in all parts of the boiler and in the chimney, and/or to dilute the flue gas through or to choose a corrosion resistant chimney. The aim of this project has been to investigate whether it is possible to absorb the acid species through additives added in the fuel or in the supplied air. Measures were performed with the addition of 1-2 weight % of additives in a 20 kW boiler. Lime stone (calcium carbonate) and sodium bicarbonate were chosen. They are not dangerous to handle and are ready available. In larger quantities, the price for lime stone is 1850 SEK per metric ton and for bicarbonate 3000 SEK per metric ton. If the price of oat is 0.85 SEK, the price increase for each percentage of addition is 2.2 or 3.5 % respectively. The results show reductions between 20 and 40 % of sulphur dioxide and hydrochloric acid. Additives mixed in the fuel affected the combustion and the emissions of unburned species increased and the efficiency of the boiler was decreased. When bicarbonate was used, sintered lumps were found in the burner after the test. Lime stone added in the supplied air did not affect the combustion. When bicarbonate was added in the supplied air increased sintering was noticed in the burner. Measured dust emissions indicate that addition of bicarbonate in the fuel may lead to an increase in dust emission. Lime stone added in the fuel decreased dust emissions. Lime stone added in supplied air increased dust emission because calcium particles that followed the gas flow without reacting. A more exact interpretation of how the additives influence on dust emission demands increased knowledge and experiences from the area. The influence of additives on dust emissions is an interesting lead that should be followed. Today, boilers larger than 500 kW in urban areas often have a maximum allowed emission of 100 mg/Nm3, or even lower, which is difficult to reach when combusting energy grain. A reduction of 20-40 % of sulphur and chlorine is hardly enough to guarantee that corrosion is avoided. A burner of this size is built with small margins and a disturbance, in this case, ”junk in the fuel” easily influence on the combustion. It is possible that in a larger boiler a higher percentage of additives could be used without influencing the combustion.