  This paper addresses the transmission network expansion planning problem
considering storage units under uncertain demand and generation capacity. A
two-stage adaptive robust optimization framework is adopted whereby short- and
long-term uncertainties are accounted for. This work differs from previously
reported solutions in an important aspect, namely, we include binary recourse
variables to avoid the simultaneous charging and discharging of storage units
once uncertainty is revealed. Two-stage robust optimization with discrete
recourse problems is a challenging task, so we propose using a nested
column-and-constraint generation algorithm to solve the resulting problem. This
algorithm guarantees convergence to the global optimum in a finite number of
iterations. The performance of the proposed algorithm is illustrated using the
Garver's test system.
