Secondary reserves Introduction Because electricity is a product that can’t be stored as such, there must always be a balance between injection (production & import) and offtake (load & export). Maintaining this balance ensures that the frequency remains at 50 Hz. Secondary reserves are one among the resources Elia has to balance its zone, being Belgium. The secondary reserves are reserves that are activated automatically based on imbalances of the Belgian zone. Elia transmits a dynamic and continuous setpoint from its control center to the participating suppliers, who alter their production automatically based on this setpoint. This alteration will help to restore the balance in the Belgian zone. There are two types of regulation: ● ●
Upwards regulation: Elia can ask to produce more electricity than scheduled Downwards regulation: Elia can ask to produce less electricity than scheduled
All suppliers of secondary reserves are activated simultaneously and pro rata based on their selected capacity of secondary reserves (see selection).
Reservation of capacity and Free bids 1
Contracted capacity: In order to guarantee a good regulation, Elia requires a total capacity of 140MW upwards and downwards secondary reserves at all times. Therefore Elia contracts a total capacity of 140MW at different suppliers who must make this capacity available at all times. The capacities that are contracted, are split up: ● ●
for upwards and/or downwards regulation 2 per tariff period: peak/ off-peak
When a supplier is not able to make the contracted capacity available for a certain amount of quarter hours, he has the possibility to transfer his obligation to another party - who has a contract for secondary reserves with Elia - via the daily secondary market. Therefore both parties must agree bilaterally and communicate the transfer and the period for the transfer to Elia. Free Bids: All parties that have signed a contract for the provision of secondary reserves with Elia (even with a reserved capacity equal to 0MW), can voluntarily offer, day-ahead, a (extra) volume of secondary reserves for the next day. For the activation, Elia will select the cheapest offers(see remuneration and selection)
1 2
Required volume for 2012 and 2013 Peak hours: from 8h to 20h, Monday till Friday Off-peak hours: from 20 h to 8h and from 8h to 20h during the weekend |Page1 of 5