Coordinated Capacity Calculation
Coordinated Capacity Calculation (CCC) is one of core RCC services established with a goal to allocate available cross-border electricity transfer capacity for different time horizons, in order to maximise transfer capacity offered to the market.
Capacity Calculation Region (CCRs) represents the geographic area in which unique CCC methodology is applied. CCRs are established by Agency for the Cooperation of Energy Regulators (ACER) and currently there are 12 CCRs. CCC is performed in two distinct time frames, each governed by specific European network codes.
YEAR-AHEAD AND MONTH AHEAD
Long term capacity calculation
Long-term CCC ensures that optimal cross-border capacity is made available to the market well in advance. It is governed by the Network Code on Forward Capacity Allocation (FCA), which allows market participants to secure transmission capacity on cross-border lines ahead of time — providing a form of trade insurance.
DAY-AHEAD AND INTRADAY
Short-term capacity calculation
Short-term CCC is governed by the Network Code on Capacity Allocation & Congestion Management (CACM), which defines two permissible approaches for calculating cross-zonal capacity: the Flow-Based (FB) approach and the Coordinated Net Transmission Capacity (CNTC) approach.
SCC performs the CNTC approach as part of a dry-run day-ahead CCC process for its TSO service users. Every Monday, SCC collects D-2 Individual Grid Models (IGMs) from SEE TSOs and performs the day-ahead CCC process for Wednesday, creating D-2 Common Grid Models (CGMs) for the SEE region in advance.
Capacity Calculation
CNTC approach
Under the CNTC approach, the key capacity values are calculated as follows:
TTC – Total Transfer Capacity: maximum cross-border capacity compatible with operational security standards.
TRM – Transmission Reliability Margin: a security margin accounting for forecast uncertainties and real-time deviations.
NTC – Net Transmission Capacity: TTC minus TRM.
ATC – Available Transfer Capacity: NTC minus Already Allocated Capacity (AAC) — the capacity remaining available for further commercial activity.
