A high penetration of distributed generation in electricity networks makes it necessary to adapt the network to the new conditions of generation and consumption. Storage units can be converted within a few years in another element of power grids. Therefore, it is necessary to analyze the network to determine the optimal location of distributed generation, which lines need to be built or where to install the storage units. This paper presents a model of power network planning which takes into account the effect of the expansion of distributed generation. The results obtained show the continuing replacement of conventional generation by distributed generation and the importance of storage units in this process of replacement.