I don't know if this makes a difference, and I'm well aware of the laws of thermodynamics, including experiments I've seen that seem to violate those laws, but that's another conversation. Point was is to heat something portable by conventional electricity (plugged into the wall) granted it would take a lot of juice to store your heat in your substance, but who cares about taking power from the grid. Point is to store it in a substance to then transport to a vehicle. Use the heat at one end to create steam/pressure whatever to spin a turbine to spin a generator, just like steam from burning coal, except your not necessarily burning anything, just heating something to extreme temperatures that creates a similar amount of heat as burning coal or what not. If that makes any sense, and I do appreciate you indulging a non-engineer. Also, would it serve an efficient enough purpose to also utilize an extremely cold end (with say dry ice, a substance readily available) to draw an extreme at one end to help with the pressure? Also, I realize your heat source would eventually cool down and the dry ice would eventually evaporate, but if you could get enough working time out of it, it may be worth it.