Transmission capacity at borders
Belgium lies at the heart of the European interconnected grid and is a crossroads for electricity exchanges between countries within that grid.
The Belgian electricity grid forms part of an interconnected system stretching from Portugal to Poland. The available transmission capacity at national borders is determined, amongst other factors, by:
- the topology of the European grid (i.e. what components are in service and how they are interconnected);
- commercial exchanges between the countries within the grid;
- periods during which components of the 380/220-kV grid are taken offline (transmission lines, phase-shifting transformers, shutdown of main generation units) in Belgium or in neighbouring countries.
Such factors can have a major impact on the situation in Belgium, which, after all, lies between countries such as France, the Netherlands and Germany which may, depending on the situation on their grid and/or market conditions, export or import significant quantities of electricity.
In view of the way in which the European electricity grid is intermeshed (rather like a spider's web, the high-voltage grid comprises a series of 'loops' allowing electricity to circulate via different paths), any transaction between two countries is partially routed via neighbouring countries' grids and as such gives rise to unscheduled flows in those countries (i.e. energy flows which are not part of their own commercial energy exchanges but which transit them 'freely').
As far as Elia is concerned, these flows prompt considerable uncertainty when calculating the exchange capacity with neighbouring countries. The large-scale advent of energy generated from renewable sources, primarily in Germany, is causing exchanges to vary further still and is thus heightening uncertainty with regard to unscheduled flows.
Click here for further information on Elia's calculation methods.
Exceptional capacity coordination measures will be taken by Elia, RTE and TenneT in case of scarcity during this winter (PDF).