This is the fifteenth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. At AEP's Gavin Plant, data from the corrosion probes showed that corrosion rate increased as boiler load was increased. During an outage at the plant, the drop in boiler load, sensor temperature and corrosion rate could all be seen clearly. Restarting the boiler saw a resumption of corrosion activity. This behavior is consistent with previous observations made at a 600MWe utility boiler. More data are currently being examined for magnitudes of corrosion rates and changes in boiler operating conditions. Considerable progress was made this quarter in BYU's laboratory study of catalyst deactivation. Surface sulfation appears to partially suppress NO adsorption when the catalyst is not exposed to NH3; NH3 displaces surface-adsorbed NO on SCR catalysts and surface sulfation increases the amount of adsorbed NH3, as confirmed by both spectroscopy and TPD experiments. However, there is no indication of changes in catalyst …