  We theoretically study the electrical, thermal and thermoelectric transport
properties of graphene nanoribbons under torsional deformations. The modelling
follows a nonequilibrium Green's function approach in the ballistic transport
regime, describing the electrical and phononic properties through
\textit{ab-initio} density functional theory and empirical interatomic
potentials, respectively. We consider two different types of deformations, a
continuous twist of a given angle applied to the nanoribbon, and two
consecutive twists applied in opposite angular directions. The numerical
results are carefully analysed in terms of spatially-resolved electron
eigenchannels, polarization-dependent phonon transmission and thermoelectric
figure-of-merit.
