For a sustainable future, it is essential to prepare gas turbines for the use with biogenic residual and waste materials. One problem that needs to be solved when using these fuels is the problem of deposits, mainly due to their ash composition with low melting temperature. For this reason, the deposition behavior caused by the ashes of biogenic residual and waste materials must first be understood before suitable countermeasures are taken in the second step. At first, an exemplary fuel composition was created in this work. In the next step, a thermodynamic calculation typical for the utilization of these materials was carried out with this composition. As part of this work, physical processes that mainly lead to the deposition of fly ash particles were also discussed. Finally, typical adhesion models were listed in the literature and applied to the calculated particle composition. A viscosity and energy model was used to carry out the calculations. The results show a high influence of phosphor on the deposits. Overall, the calculated ash showed a uniform proportion of oxides, phosphates, sulphides, slag and salts. It could also be shown that salt condensation can have a significant influence.