EIRGRID HAS defended its proposal to build an interconnector in the northeast which would link electricity grids in the North and South.
Residents of the northeast, led by groups including the North East Pylon Pressure Group, have argued that large pylons and high-voltage overhead lines are not appropriate in the area.
More than 900 submissions have been made to An Bord Pleanála relating to the plan for some 140km of 400 kilovolt overhead line on lattice towers from Meath to Tyrone.
A public oral hearing into the plan in Carrickmacross, Co Monaghan, was attended by hundreds of people as it began yesterday.
The part of the electricity line within the State will cover 100 kilometres and will pass through Meath, Cavan and Monaghan before crossing the Border to a new substation in Co Tyrone.
People living in the northeast have suggested a number of options, including underground cables along existing rail lines.
This would not interfere with animal or human health and would not have a negative effect on farming or tourism, they argue.
However, many of the objectors have accepted in their submissions that improvement of the electricity infrastructure is needed.
Louis Fisher of Eirgrid said yesterday that the development was needed to improve electricity competition by reducing constraints to the all-island electricity market, to support renewable power generation, to improve the security of supply and to maintain the reliability of the network in the northeast, .
If the interconnector was not built, it would put the reliability of customer supply in the northeast at risk by 2017, he said.
The second interconnector was also needed in case of an unplanned outage at the existing interconnector from Louth to Armagh, which would have serious consequences.
This outage would cause “widespread disconnection of customers in one part of the system and system instability or even collapse in the other”, Mr Fisher said.
The risk and serious potential consequences of power system separation resulted in more expensive generation and higher electricity costs.
There was nothing particularly unusual about this project in its design, construction or operation, said Aidan Geoghegan technical specialist with Eirgrid.
He said there was no difference between this and more than 400 kilometres of line already operating safely.
However, the masts in this project would have less of a visual impact, he said.
Mr Geoghegan dismissed submissions that underground cables should be used. Overhead lines were equally as safe.
Forced outage duration of an underground cable would be at least 10 times longer than an overhead line because they take significantly longer to repair. While an overhead line might take a day or even repair itself the underground cables could take four weeks to fix, he said.
Despite concerns about fatalities with overhead cables, there was not a single fatality on overhead cables (110kv, 220kv or 400kv) since records began in 1995, Mr Geoghegan added.
Underground cables were used in specific circumstances such as under the sea as in the proposed Ireland and Wales interconnector, he said.
They were also estimated to cost up to 10 times more to construct than overhead lines.
Eirgrid has also dismissed calls for using the route of disused railway lines or placing cables under roads as railway lines and roads in the northeast would be too narrow for the development.
The hearing is expected to last until the end of June and local authorities, residents’ groups and the Department of the Environment and An Taisce will appear before the board.