The effect of co-firing bark or wood powder in a recovery boiler is studied. The effect of increased NPEs in the liquor and lime cycles, the FMT and sticky dust and the smelt composition is assessed by using simulation tools. The results indicate that generating an additional 22-39% HP steam for power production by firing wood powder in the recovery boiler is a viable option, if Cl and K are purged from the ESP dust by a treatment unit. The smelt is enriched with the same proportion of NPEs as the as-fired liquor.