Electricity Production from Renewables Energies

6.1. From a centralized network to a decentralized network

The conventional organization of electrical networks developed in the 20^th Century revolves around a transport network receiving the electrical power, which is produced in centralized units (nuclear, thermal or hydraulic power stations) and transmitted to commercial or private consumers via a distribution network [KUN 94, HAB 09]. Major industrial consumers can be directly supplied from the transport network, such as the rail network.

6.1.1. The transport network

The transport network is the basic structure of an electrical network. The powers for national and international consumers go through this network. Its exploitation is essential for the quality of electricity supply. A problem on this network can have repercussions for the entire territory, but also for other European networks (there can be a snowball effect, which could lead to a collapse or a black-out).

Transport lines enable us to transport electric energy from production sites towards the sites of use. In France, with an electrical network spreading over a million kilometers, the production unit output voltage had to be raised, in order to reduce conveyance losses, all the while knowing that electric generators cannot directly produce such voltages. The voltage field of this network is HV (more than 50 kV). Its voltage levels are standardized. In France, the following values are chosen: 400, 225, 90 and 63 kV (exceptionally, 150 and 45 kV). Figure 6.1 shows ...