SIDC (Single Intraday Coupling)
SIDC is the European mechanism for continuous cross-border intraday electricity trading after the day-ahead auction has closed. It connects NEMO trading systems through common infrastructure: the Shared Order Book, Capacity Management Module and Shipping Module, plus intraday auctions for pricing scarce intraday cross-border capacity.
SIDC, Single Intraday Coupling, is the European mechanism for continuous cross-border intraday electricity trading. After the day-ahead market has closed, market participants can keep adjusting positions closer to delivery. SIDC connects NEMO trading systems through a common IT architecture built around the Shared Order Book, the Capacity Management Module and the Shipping Module.
How it differs from SDAC
SDAC is a discrete auction: one central clearing run for the next day. SIDC is continuous: orders match as soon as a compatible counter-order and enough cross-zonal capacity exist. Continuous intraday capacity is allocated first come, first served, while companion intraday auctions price scarce intraday cross-border capacity at defined auction times.
Why traders use it
Intraday trading is where forecast errors get repaired. Wind, solar, demand and asset availability all change after the day-ahead auction. SIDC gives BRPs, generators, suppliers and aggregators a way to buy or sell closer to real time before imbalance settlement starts pricing the deviation. For battery and flexibility operators, SIDC is often the bridge between day-ahead arbitrage and balancing-market activation.