The performance of the dual fluidized bed gasification plant Oberwart was evaluated by means of an extensive measurement campaign and calculation of mass and energy balances using IPSEpro. Process simulation was also applied to identify future optimization potentials. Different aspects are discussed such as the reduction of gasification temperature and the reduction of steam for gasification and air for combustion. Gasification pilot plant experience is integrated in the simulation models to increase significance of the simulation results. The mass and energy balances confirm that the performance of the CHP plant Oberwart is highly satisfactory and currently achieves an electrical efficiency of 29%. The variations of plant parameters provide deeper insight in the process itself and show interdependencies of different process units. With lower gasification temperatures and reduction in combustion air, the electrical efficiency can be increased to 31%. (C) 2015 Elsevier B.V. All rights reserved.