  Understanding the role of classical and quantum correlations in work
extraction is a problem of fundamental importance in thermodynamics. We
approach this problem by considering that, in closed quantum systems, the
maximum cyclic work extractable is equal to the ergotropy. Thus, we aim to
identify and investigate the contributions to the ergotropy coming from
different kinds of initial correlations (total, classical, discord and
entanglement correlations). By doing so, we have introduced and studied
quantifiers of correlations which are based on ergotropy. In particular, our
results suggest that only discord correlations always give a positive
contribution to work extraction, while total, classical and entanglement
correlations can reduce the work extraction.
