  We analyze the nanocaloritronic performance of an interacting quantum dot
that is subject to an applied bias and an applied temperature gradient. It is
now well known that, in the absence of phonon contribution, a weakly coupled
non-interacting quantum dot can operate at thermoelectric efficiencies
approaching the Carnot limit. However, it has also been recently pointed out
that such peak efficiencies can only be achieved when operated in the
reversible limit, with a vanishing current and hence a vanishing power output.
In this paper, we point out three fundamental results affecting the
thermoelectric performance due to the inclusion of Coulomb interactions: a) The
reversible operating point carries zero efficiency, b) operation at finite
power output is possible even at peak efficiencies approaching the Carnot
value, and c) the evaluated trends of the the maximum efficiency deviate
considerably from the conventional {\it{figure of merit}} $zT$ based result.
Finally, we also analyze our system for thermoelectric operation at maximum
power output.
