Solving for load (machine) power, cable resistance, and source voltage, it's possible to solve for power draw.
The voltage breakdown would work as it already does, and there's the potential for a temperature-based breakdown system, albeit with more complexity.
The voltage can be solved with this formula:
P = (4*Pl)/(2+sqrt(1-(4*Pl*R/V**2)))
P is the power expended by the source of current,
Pl is the power received by the machine,
R is the resistance of the cables connecting the machine to the source of current,
and V is the voltage of the system.
This would allow for the power system in IC^2 to accurately model ideal loads and ideal resistors in series. Of course, this system would put a greater computational drain on the system, but I think it would be insignificant compared to rendering or block updates.