EirGrid Group Publishes T-4 Capacity Auction Results

Capacity auctions are a key element of the all-island wholesale electricity market and are designed to deliver a reliable electricity supply at the least possible cost.  The auctions also aim to encourage new and efficient power plants into market.

This auction, known as a T-4 auction because it secures capacity four years in advance, ran on 23 March, procuring sufficient capacity to meet security of supply for the period 1 October 2026 to 30 September 30 2027.

This auction secured a total of 7,204 megawatts (MW) of capacity, of which 1,519 is new generation. Gas turbines comprise most of the new generation, complemented by new interconnection, battery storage and demand side units. The auction clearing price was €83,050 per MW per year.

A total of €698 million of capacity payments will be paid to generators who were successful in this auction.

The capacity required from the auction considered peak demand, security of supply, as well as the reliability and performance of generators, and a range of demand forecasts and interconnection.

The auctions are run by EirGrid and SONI (the Electricity System Operator for Northern Ireland) in their roles as Transmission System Operators in Ireland and Northern Ireland respectively, through the joint venture SEMO (Single Electricity Market Operator).

The auctions were designed by the electricity regulators in Ireland and Northern Ireland to ensure sufficient capacity is secured to meet demand across the island. The next T-4 auction is scheduled to take place this September and covers the period 2027 to 2028.

The provisional results are available at Provisional Capacity Auction Results Report on the SEMO website.