EirGrid has identified three optimum link-up locations for a new 250km high voltage pylon route across Leinster and Munster.
The energy network company said the 500 million euro project would be best suited to a corridor from Knockraha in Cork to Great Island in Wexford and Dunstown in Kildare.
But as an eight-week public awareness and consultation period began, EirGrid insisted no application for the build would be lodged before the end of 2015.
Under initial proposals the 400kV Grid Link corridor would be overhead, at least 250km long and with pylons every 4km and big enough to bring wind energy to 750,000 homes.
Pat Rabbitte, Minister for Communications, Energy and Natural Resources, said it will provide a secure, long-term electricity supply for homes and businesses in the south and east.
"The grid link project will reinforce the electricity grid and have direct economic benefits for our local communities. I encourage people to engage in the public consultation and provide feedback to EirGrid," he said.
EirGrid said the optimum connection points in Cork, Wexford and Kildare would house transmission substations. An area covering Carlow, Cork, Dublin, Kildare, Kilkenny, Laois, Limerick, Tipperary, Waterford, Wexford and Wicklow has been chosen for possible routes.
EirGrid, which has already faced massive opposition to high voltage lines in Co Meath and the Midlands, said the development was needed to plug gaps in the transmission system in the south and south-east.
Dermot Byrne, chief executive of EirGrid, said the link is vital if the goal of 40% electricity from wind, wave and tidal renewables is to be reached by 2020.
He said: "The project will help enable Ireland to shift from a heavy reliance on imported fossil fuels to more sustainable sources of energy. It will also help ensure that the most efficient electricity generators in the south and east are utilised in the most effective way."