Technical advisory board members of eXtremeMAT, a national effort focused on developing next-generation extreme-environment materials for use in advanced fossil energy power systems that operate in extreme environments, met at NETL’s Pittsburgh site Aug. 13, 2019, to assess progress and map plans for future research. Fossil energy transformational power technologies like ultra-supercritical steam plants and supercritical carbon-dioxide power have the potential to increase efficiencies and bolster clean coal efforts because they operate at higher temperatures and pressures. However, these technologies operate in harsher, more corrosive conditions compared to traditional power plants. In addition, current fossil power plants are increasingly subjected to cycling conditions due to increases in renewable energy sources onto the electricity grid. Accelerating the development of improved steels, superalloys and other advanced alloys is of paramount importance in deploying materials solutions to address materials challenges associated with both the existing fleet and future power systems.