hmm…i don think what your asking makes any sense. first i would like to point out that a FORCE cannot be a ENERGY. i mean they both are different quantities. its like saying i am measuring 1 Kg wait from a meter scale. so your question can be countered this way. but modifying your question, it can be asked that “if magnets can produce continues field then cant that field be used to do work(energy) continually ?” well there is nothing amusing in this as even two persons standing would attract them self due to gravity continuesly and so can work be gained out of it. but the problem lies in the fact that its not the field that is required for your so called “energy” it is the “change in field that is required”. and to get that change in field one external agent has to do work! thus again boils down to the point that energy(work) can be converted from one another but not created !