"Photovoltaics (PV) based on Silicon (Si) semiconductors is one the most growing technology in the World for renewable, sustainable, non-polluting, widely available clean energy sources. Theoretical and applied research aims at increasing the conversion efficiency of PV modules and their lifetime. The Si crystalline microstructure has an important role on both issues. Grain boundaries introduce additional resistance and reduce the conversion efficiency. Moreover, they are prone to microcracking, thus influencing the lifetime. At present, the existing standard qualification tests are not sufficient to provide a quantitative definition of lifetime, since all the possible failure mechanisms are not accounted for. In this proposal, an innovative computational approach to design and durability assessment of PV modules is put forward. The aim is to complement real tests by virtual (numerical) simulations. To achieve a predictive stage, a challenging multi-field (multi-physics) computational approach is proposed, coupling the nonlinear elastic field, the thermal field and the electric field. To model real PV modules, an adaptive multi-scale and multi-field strategy will be proposed by introducing error indicators based on the gradients of the involved fields. This numerical approach will be applied to determine the upper bound to the probability of failure of the system. This statistical assessment will involve an optimization analysis that will be efficiently handled by a Mathematica-based hybrid symbolic-numerical framework. Standard and non-standard experimental testing on Si cells and PV modules will also be performed to complement and validate the numerical approach. The new methodology based on the challenging integration of advanced physical and mathematical modelling, innovative computational methods and non-standard experimental techniques is expected to have a significant impact on the design, qualification and lifetime assessment of complex PV systems."