Balancing market

Deviations between injection to and withdrawal from electricity networks must constantly be balanced out by increases or reductions in the output of control energy suppliers’ power stations. Distinctions are drawn between primary, secondary and tertiary control energy. These control energy reserves differ in terms of the speed with which they can be activated and their utilisation adjusted. Primary and secondary control energy are automatically called off from regulable power stations. Tertiary control energy is requested from suppliers by means of telephoned despatch instructions.
Primary control energy must be available within 30 seconds, secondary control energy within five minutes, and tertiary control energy within ten minutes.

Since 1 January 2010 Austrian Power Grid AG (APG) has organised the reservation of primary control energy capacity by holding weekly tenders. At present APCS is not concerned with the supply and settlement of primary control energy services.
Secondary control energy is automatically activated to free up the primary control system so that it can return to fulfilling its network balancing function.
APG assumed responsibility for the secondary and tertiary control markets on 1 January 2012. APCS passes on the cost of the secondary control services to the balance groups on a cost reflective basis, as a component of the overall balancing charges.
The suppliers are responsible for obtaining tertiary control energy. It is employed where extended use is made of secondary control energy – typically during power station outages – so as to free up the latter for new network control tasks.
To ensure that there are adequate reserves of balancing energy, the APG control area has market makers as well as balancing energy suppliers. The bidders in the weekly market maker tenders undertake to ensure that sufficient quantities of tertiary control energy are always available.

Balancing energy supplied or taken to compensate for deviations between schedules and actual exchanges of electricity on the RGCE grid in the previous week (unintentional deviations) is sourced by means of weekly tenders on the Austrian power exchange, EXAA Energy Exchange Austria.

APCS is responsible for the clearing and settlement of balancing energy (apart from primary control energy), and posts comprehensive information on the control energy tenders (summary list of bids, bid call-offs, tender details, etc.) in the restricted area of the APCS clearing platform for the use of balancing energy suppliers that have registered with the site.