A thermoelectric power generation system using thermal energy of little temperature difference has many advantages, such as high reliability, greater safety and maintenance-free operation. as heat transfer augmentation is required to increase the electric power output, a smooth arc-shaped turbulence promoter on the inside surface of the pipe has been proposed from a standpoint of fouling removal by sponge balls. Two types of thermoelectric power generators using cold and warm water pipes with arc-shaped cascade promoters were made. Performances of heat transfer and electric power generation were measured. The optimum condition for power generation is made clear in consideration of pumping power loss. It is concluded that the power generation performance for a pipe with arc-shaped turbulence promoters is better than that for a smooth pipe, in spite of its larger pressure loss.