APCS carries out a monthly clearing process. This depends on every system operator sending us quarter-hourly metering data, including metering data from individual generating units, and network transfer volumes.
Electricity wholesalers must provide us with information on their business activities, in the form of sales schedules and consumption forecasts. To complete the information loop, the control area manager informs APCS of import and export volumes, and the quantity of control energy required by the entire network.

As would be expected, there are sometimes considerable differences between forecast and actual consumption and generation, which could endanger network stability. However, the control area manager has tools that it can use to bridge these gaps.
Normally, these mechanisms involve using power stations that can be started up or backed down at short notice.

In Austria, the electricity wholesale and retail markets, and also trading in the energy required to maintain network stability – so called “balancing energy” – have been liberalised.
Austrian Power Grid AG has been managing all trading in balancing energy since 1 January 2012. APCS provides the registered balancing energy suppliers with the information they need on tenders, bids and call-offs, via its clearing platform.
Competitive tenders ensure that the lowest bids are taken up when calling off energy to balance the network. The system gives all concerned incentives to make their generation and consumption forecasts as accurate as possible, since no one wants to pick up a big bill for balancing energy.

During the monthly clearing process, the quantities of balancing energy provided and used by each market participant in the previous month are calculated on a quarter-hourly basis.

A market-based clearing price model is used to set the quarter-hourly clearing prices. There is just one price per time unit. Both the rates established by the balancing market and the prices on the power exchange are included in the clearing price calculations. The clearing price model is designed in such a way that heavy balancing energy needs mean high clearing prices. The model takes account of the cost of the various forms of balancing energy utilised in the course of a month (day-ahead market, secondary control market, crossboarder exchanges and the market maker).

Clearing prices are assigned to the quarter-hourly quantities of balancing energy that arise, ensuring that the parties that cause the need for control energy also carry the cost.

This is the basis on which all the market participants in the APG control area (BGRs, SOs and balancing energy suppliers) are invoiced/credited.