  For genuine non-equilibrium states that even at fixed external control
parameter exhibit dissipation, we extend the Hatano-Sasa equality to processes
with feedback control. The resulting bound on the maximal extractable work is
substantially sharper than what would follow from applying the Sagawa-Ueda
equality to transitions involving such states. For repeated measurements at
short enough intervals, the power thus extracted can even exceed the average
cost of driving as demonstrated explicitly with a simple, analytically solvable
example.
