The Day-Ahead Market (MGP) hosts the majority of electricity trading transactions.
In the MGP, blocks of energy pertaining to market time intervals of the following day are traded.
Participants in this market submit bids/offers in which they specify the quantity and the maximum/minimum price at which they are willing to purchase/sell.
Bids/offers are accepted after the closing of the market session, on the basis of economic merit and in compliance with the transit limits between zones. The MGP is therefore an auction market and not a continuous trading market.
All supply offers and demand bids referring to both injection and withdrawal portfolios that are accepted in the MGP are valued at the marginal clearing price of the zone to which they belong. This price is determined, for each minimum market time interval, by the intersection of the demand and supply curves and it differs from zone to zone when transit limits are saturated..
For each demand bid accepted in the MGP sessions in respect of withdrawal portfolios belonging to a geographical market zone, GME will determine the compensatory component that the Participant submitting the bid is required to pay (if negative) or to receive (if positive); this component is equal to the product between the accepted quantity and the difference between the above-mentioned relative marginal clearing price and the PUN Index GME.
GME acts as a central counterparty.