Intraday markets are an important tool for market participants to balance their positions as injections and/or withdrawals may change between the day-ahead and real-time operations. In addition, the growth of intermittent renewable energy sources has increased the importance of relying on efficient intraday markets.

XBID

In the European context, the CACM Regulation 2015/1222 established the Target Model for the European integrated electricity market in the intraday timeframe, providing that the European Single Intraday Coupling (SIDC) should be based on energy trading under a continuous trading mechanism, in which the interconnection capacity available between the different zones of the SIDC is implicitly allocated simultaneously with the matching of buy and sell orders submitted in different zones.

The European SIDC solution is based on a centralised IT platform, called XBID. The platform integrates the continuous-trading intraday markets of 25 countries: Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Hungary, Estonia, Finland, France, Germany, Greece, Italy, Latvia, Lithuania, Luxembourg, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, and Sweden.

IDAs

In addition to the continuous trading mechanism, the European Target Model also provides that intraday interzonal transmission capacity should be allocated via three pan-European implicit auctions (Intraday Auctions - IDAs). The purpose of IDAs is to harmonise the computation of cross-border capacity and assign a price to such capacity concurrently with its allocation.
With ACER’ Decision n. 01/2019 of 24 January 2019, in application of art. 55 of CACM Regulation, the IDA methodology entered into force for the pricing of cross border capacity allocated in the intraday markets of the different EU Countries.

In the context of interest for Italy, ARERA’ Decision 212/2024/R/eel established that, starting from 13 June 2024, the continuous trading mechanism of XBID should be integrated with the three IDAs on the Italian borders with Austria, France, Slovenia, and Greece, via the Euphemia algorithm.
With their implementation, IDAs replaced the previous Complementary Regional Intraday Auctions (CRIDAs). Consequently, the coupling mechanism (of which the implicit intraday auctions managed by GME in the MI-A are an integral part) now includes not only the borders with Greece and Slovenia (previously included in CRIDAs), but also the borders with Austria and France.

More information here: 

SIDC 
IDA pre-launch Event