Superconducting power cables are one of the most promising energy applications of high-temperature superconductors, Losses in superconducting power cables are mainly due to AC, thermal and dielectric effects. The interplay of cable geometry, operating conditions, transmitted power, and the resulting losses are considered. The design studies indicate that for Bi-2223 cables with warm dielectric an operating temperature well below 77 K is favoured. For operating temperatures of 45-50 K low-cost Bi-2212 superconductors could be an alternative to Bi-2223. The superconductor properties required for the cable application are briefly dis cussed. Finally, a design concept for a loss-optimised superconducting 112.5 MW single-phase transmission cable is presented. (C) 1999 Elsevier Science Ltd. All rights reserved.