The companies have signed contracts with Siemens Energy for the creation of converter stations in Ireland and France to support the Celtic Interconnector project.
French cable manufacturer Nexans has also been contracted to design and install a 575km cable for the project.
The Celtic Interconnector will link Ireland’s southern coast with the northwestern coast of France via the cable, which will be laid between East Cork and the coast of Brittany.
This cable will have the capacity to import and export enough electricity to power 450,000 homes.
The project will link substations at Knockraha in Cork, Ireland; and La Martyre, France.
It is expected to become operational by 2026 and will be the first interconnector between Ireland and continental Europe.
The Celtic Interconnector is being funded in part by the European Union, which has categorised it as a Project of Common Interest (PCI).
EirGrid CEO Mark Foley said: “The Celtic Interconnector is a key part of EirGrid’s strategic goal to transform Ireland’s power system and increase the use of renewable electricity.
“Interconnection with France makes the power system more resilient and efficient and allows renewables to become the primary energy source on the national grid.”
The companies previously received €530.7m of Connecting Europe Facility (CEF) financing for the project in 2019.
EIB vice-president Ambroise Fayolle said: “Investment in cross-border electricity interconnectors is essential to deliver climate and energy goals.
“The European Investment Bank is pleased to support the Celtic Interconnector as part of our support for climate action and energy security across Europe.”