The European Union aims to become the first continent with net zero greenhouse gas emissions by 2050. The conversion of waste heat into electricity via thermoelectric effects is seen as a key strategy to achieve this goal. Thermoelectric generators (TEGs) are active devices that consist of such conversion. The use of nanoscale materials can improve the efficiency of TEGs. Furthermore, current research shows that one- and two-dimensional materials have superior thermoelectric effects compared to three-dimensional ones. Nanotechnology has accelerated the development of new thermoelectric materials since nanoscale materials allow better control of transport coefficients. The discovery of more efficient materials is a key to improving the performance of TEGs. The analysis of coupled transport phenomena is one of the most outstanding aspects of non-equilibrium thermodynamics. In this talk attention is paid to thermoelectricity, i.e., the coupling of heat and electricity. We propose a theoretical model which goes beyond the usual relations employed at macro-scale to describe thermoelectric effects. Such model introduces both non-local and non-linear effects which should be taken into account in view of the possible applications of thermoelectric effects at nanoscale. The proposed model is employed to investigate how those non-local and non-linear effects may affect the propagation of waves. In nanosystems nonlocal and nonlinear effects may strongly influence both electronic and optical properties [1, 2] it could be, therefore, important to examine more deeply those effects by introducing generalized nonlinear heat-transport equations beyond the classical Fourier law, in order to analyze the propagation of small-amplitude waves. The theoretical model suggested in the talk offers new strategies to optimize thermoelectric effects and could lead to significant improvements in TEGs performances. REFERENCES [1] Di Domenico, M., Jou, D. and Sellitto, A. Nonlinear heat waves and some analogies with nonlinear optics. Int. J. Heat Mass Transfer (2020) 156: 119888. https://doi.org/10.1016/j.ijheatmasstransfer.2020.119888 [2] Di Domenico, M., Jou, D. and Sellitto, A. Heat-flux dependence of the speed of nonlinear heat waves: Analogies with the Kerr effect in nonlinear optics. Int. J. Therm. Sci. (2021) 161: 106719. https://doi.org/10.1016/j.ijthermalsci.2020.106719