Change of method to determine the GLSK of the BE bidding zone

Dear Market Participants,

In line with article 24 (5) of the DA CCM and article 21 (5) of the ID CCM Elia would like to inform you about an upcoming change of the method to determine the GLSK of the BE bidding zone.

The Core GLSK study shows the benefits of using a GLSK-methodology that properly reflects the increasing share of renewable energies in the electrical system. Consequently, Elia will in the future introduce the use of load shift keys (LSK) in times when flexible generation is limited (i.e. in conditions of incompressibility or scarcity). GSK will remain in use too, for most of the time there will be no difference with the current method (i.e. when there is sufficient flexible generation in BE). The Core GLSK-study shows that this change will provide increased accuracy in the calculation of capacities.

In the future also, the GLSK (i.e. relative weights) will be determined on an hourly basis, instead of on a daily basis today, which also help provide better accuracy.

The new method will be applied for the DA as well as the ID timeframe. The go-live date is not yet set and will be communicated in a market message as soon as possible. The change is expected at the end of Q3 2025. 

Sincerely,

Elia Transmission Belgium