Purchase of ancillary services
Since Elia does not have its own facilities on which it can alter injection or offtake, it buys flexibility capacities, or reserves, from generators and consumers to ensure the reliability of the high-voltage grid and the quality of the energy supply. The services provided in this way are known as ancillary services.
Ancillary services can be provided by generation as well as load facilities connected to the TSO or DSO grid depending on the AS product; exceptionally this can be done as well by flexibility at neighboring transmission system operators. Elia can also buy Ancillary Services from generation units that hold a valid CIPU contract or non-CIPU grid user.
See here more information on purchases of Ancillary Services by Elia.