Abstract: A method for enhancing the flow of heavy crude oil by heating a subsea pipeline is disclosed in which a pipe-in-pipe subsea pipeline is established having a flowline for transporting well fluids in the form of an electrically conductive inner pipe concentrically surrounded by an electrically conductive protective outer pipe and the inner pipe is electrically insulated from the outer pipe along the length of the subsea pipeline. The pipe-in-pipe subsea pipeline is electrically heated continuously along its length to maintain the temperature of crude oil at a level facilitating pipeline transportation, this heating comprising passing alternating electrical current along the exterior surface of the inner pipe and along the interior surface of the outer pipe. In this manner the crude oil can be maintained at a temperature at which viscosity does not prevent efficient and economical pipeline transport.