Elia has introduced a balancing mechanism designed to maintain the balance on a national level and to control sudden imbalances between injection and offtake.
Since it is not possible to store large quantities of electricity, generation and consumption constantly need to be balanced out. The structure used to balance the grid is three-pronged:
The Belgian market forms part of the wider European electricity grid: electricity flows freely, via this grid, through 24 interconnected countries from Portugal to Poland and further east to Bulgaria.
In the event of major imbalances, each country can count on support from the others within the interconnected control area. However, such support is provided for a designated period of time only and is subject to stringent European rules.
Elia has also concluded contracts with neighbouring system operators concerning the provision and receipt of support under certain circumstances.
Every access point – whether for injection or offtake – on the Belgian electricity grid is managed by an 'access responsible party' (ARP). The ARP is responsible for balancing all offtake and injection within its customer portfolio on a quarter-hourly basis.
Where Elia identifies an imbalance between total physical injections, import and purchases on the one hand and total offtake, export and sales on the other, it will apply an imbalance tariff.
Use of system services
Where ARPs are unable to balance their customer portfolio, Elia itself may take the necessary steps to balance the control area. Since Elia does not own its own generation units, in such situations it will ask system operators to provide several ancillary services:
- primary reserve
- secondary reserve
- tertiary reserve
- via generation units (R3-PROD)
- via profile adjustment services (R3-DP)
- via sheddable customers (ICH)
- tertiary reserve via sheddable customers
- uncontracted reserve ('free bids')
- reserve contracts with neighbouring system operators
The primary and secondary reserves are activated automatically, while other reserves are activated 'manually' conformed to the balancing rules approved by the regulator.
The imbalance tariffs charged are proportional to the resources Elia is required to utilise to manage the imbalance in the control area.