I just took a look at the source paper [0] """ Although the attainable magnetic flux density limits the energy per unit volume given by Equation (1) ( B2 /2μ o

I just took a look at the source paper [0] """ Although the attainable magnetic flux density limits the energy per unit volume given by Equation (1) ( B2 /2μ o), the real limit of the energy stored in a SMES is mechanical. [...] The relation defines the minimum mass of the mechanical structure in pure tension to support the radial electromagnetic forces. Force-balanced coils [5] minimize the working stress and thus the mass of the structure. """ So it looks like they 1) don't look at cryo and 2) the limiting factor is the stress due to EM fields. [0] https://snf.ieeecsc.org/sites/ieeecsc.org/files/CR5_Final3_012008.pdf https://snf.ieeecsc.org/sites/ieeecsc.org/files/CR5_Final3_0...