The author discusses the results obtained in the field of transport properties of current driven plasmas. The power balance is analysed and the results on power absorption discussed. The energy content in the suprathermal tail that carries the plasma current can be accounted for only by collisional slowing down and therefore direct power losses from tail electrons are negligible. The confinement time of the thermal bulk of the plasma degrades with the input power but displays a positive scaling with plasma density. Control of the current profile and of the MHD activity can considerably improve thermal diffusivity especially in the plasma centre. The threshold for the onset of the H-mode can be lowered in the presence of the fast electron tail and the frequency of the ELMs can be influenced by current profile control.