  We analyze the role of indirect quantum measurements in work extraction from
quantum systems in nonequilibrium states. In particular, we focus on the work
that can be obtained by exploiting the correlations shared between the system
of interest and an additional ancilla, where measurement backaction introduces
a nontrivial thermodynamic tradeoff. We present optimal state-dependent
protocols for extracting work from both classical and quantum correlations, the
latter being measured by discord. We show that, while the work content of
classical correlations can be fully extracted by performing local operations on
the system of interest, the amount of work related to quantum discord requires
a specific driving protocol that includes interaction between system and
ancilla.
