Despite recent years’ efforts in accelerating the transformation to a more sustainable society, the emission of greenhouse gases is steadily increasing. Although changes in favour of renewable electricity production, it is argued that, the transformation is too slow. This low transformation rate of the global electricity production calls for the need of some achieving negative emissions of CO2, which motivates that renewable fuels are used in combination with Carbon, Capture and Storage (CSS) processes. This concept is referred to as BECCS (BioEnergy, Carbon, Capture and Storage) and where the carbon source is not of fossil origin. The major drawback with BECCS techniques is the energy penalty associated with them. This energy penalty, in achieving the CO2 capturing, may be as high as 15-40% of the heat and power being produced. By increasing the efficiency of biomass-fired power plants, for instance by increasing temperature and pressure, more heat and power can be produced and still capturing carbon. This will make a need for materials with improved high-temperature mechanical properties as well as corrosion resistance. Good candidates might be found in the group of advanced austenitic steels, that have good corrosion resistance and have showed promising mechanical properties at elevated temperatures.

This work investigates three different advanced austenitic stainless steels, namely Sanicro 25, Sanicro 28 and 27Cr33Ni3Mo, which are possible candidates for high temperature components of future high-efficient biomass-fired power plants. The alloys were subjected to creep and slow strain rate testing at 700 °C, thermomechanical fatigue (TMF) and crack propagation testing during TMF in the temperature range of 100 °C up to 700 °C. Differences in mechanical properties will be discussed and related to high-temperature strength. Sanicro 25 show good high-temperature strength affecting the creep and TMF properties in a positive way. Whereas, Sanicro 28 show good TMF crack-propagation properties.