The development of renewable sources of energy combined with the European policy of integration for the electricity market is putting pressure on the transport and distribution networks for electricity. They have to adapt to new constraints, which requires them to be more flexible. The responses of network actors to these challenges differ according to the scale at which one considers them. At the European level, the trend is towards the growth of these networks as this allows the connection of new renewable sources to the market and the interconnection of States. At the local level, the rise of “smart grids” with the integration of digital management and communication technologies to network functioning, new HDVC technology, and the injection of small amounts of energy from emerging “prosumers”, open the possibility for shrinking dynamics. This brings up the question of choosing a model for the long term development of power networks and of its impact on the European power sector as a whole.