  We consider a macroscopic system in contact with boundary reservoirs and/or
under the action of an external field. We discuss the case in which the
external forcing depends explicitly on time and drives the system from a
nonequilibrium state to another one. In this case the amount of energy
dissipated along the transformation becomes infinite when an unbounded time
window is considered. Following the general proposal by Oono and Paniconi and
using results of the macroscopic fluctuation theory, we give a natural
definition of a renormalized work. We then discuss its thermodynamic relevance
by showing that it satisfies a Clausius inequality and that quasi static
transformations minimize the renormalized work. In addition, we connect the
renormalized work to the quasi potential describing the fluctuations in the
stationary nonequilibrium ensemble. The latter result provides a
characterization of the quasi potential that does not involve rare
fluctuations.
