Energy efficiency of ReBCO degaussing systems for naval vessels

Ships are predominantly constructed from magnetic steel alloys, which exhibit magnetic permeabilities typically ranging between 100 and 300. As a result, the geomagnetic field around the ship becomes distorted, an effect known as its magnetic signature. This signature can be detected from a distance using active or passive magnetic field sensors. To avoid detection, navy ships are equipped with degaussing systems that render them largely magnetically invisible. These systems consist of coils distributed throughout the ship, generating magnetic fields that counteract its magnetic signature. Depending on the vessel’s size and geometry, degaussing systems typically require currents ranging from several hundred to several thousand amperes. Due to the ohmic resistance of conventional copper coils, their power consumption is relatively high. To reduce energy demand, copper cables can be replaced with superconducting ones. When cooled below their critical temperature Tc, superconductors exhibit negligible electrical resistance and can carry current densities 100 to 1000 times higher than normal metals. In this project, a ReBCO-based degaussing system was compared to a conventional one, focusing on the cooling power required versus the electrical power consumed. For small-scale ReBCO systems, cooling demands result in higher overall power consumption than conventional setups. However, as system size increases, ReBCO power consumption grows more slowly, leading to a crossover point. The exact ship length at which ReBCO becomes more energy-efficient depends on factors such as cryocooler efficiency, insulation heat leakage, and copper cable current density. Estimates suggest that for ships around 100 meters or longer, ReBCO degaussing systems become energetically more favorable.