@Anamari and if the POA you hold permits you to submit tax returns, and there is no 'spring provision' in the POA, you should be fine to efile.....
the real issue to me is just because you have the spouse's POA doesn't mean you have the right to invoke the powers in it. Under what circumstances can you invoke the power? Some require the indiviudal to be incapacitiated before you have power - that is what I would be wary of.
