EirGrid is a state-owned company and is the independent electricity Transmission System Operator (TSO) in Ireland and the Market Operator (MO) of the wholesale electricity trading system

EirGrid’s mission is to develop, maintain and operate a safe, reliable, economical and efficient transmission system for the benefit of our customers, to deliver quality transmission and market services and to advise the Commission for Energy Regulation (CER) in relation to the security of supply.

EirGrid's role is to deliver quality connection, transmission and market services to electricity generators, suppliers and customers utilising the high voltage electricity system. We are responsible for the Grid infrastructure required to support the development of Ireland's economy, as well as connecting the Irish Grid to the European Grid. EirGrid plays a key role in the operation of the Single Electricity Market (SEM) which services the island of Ireland.

EirGrid’s day-to-day activities include:

• Controlling the flow of power across the transmission system, ensuring demand is constantly met on a 24 * 7 basis.
• Providing transmission and connection services to approx. 45 generators (including fossil plants, hydro plants and wind farms) and also to demand customers.
• Planning for the strategic development of the transmission system into the future.
• Overseeing and directing the maintenance and construction of the transmission system by the ESB.
• Facilitating the continuous operation and administration of the SEM.