This section dealt with the consideration of alternatives

Michael Fisher     Northern Standard

Kevin Traynor from Martry, Kells, County Meath, whose home is close to where the proposed interconnector would cross the River Blackwater, challenged Eirgrid’s assertion that undergrounding of this project was not a valid option to be considered.

His submission asked EirGrid to consider undergrounding all cables associated with the infrastructure in a full and properly costed way. He used the analogy that to build such an important piece of infrastructure in the provision of the nation’s future needs for electrical power, without considering the option of undergrounding, would be the equivalent of building the Eiffel Tower (Paris) in brick without considering iron as a construction material.

  1. Feasibility and technical ability to execute undergrounding.

We keep hearing from EirGrid that undergrounding of this project is not feasible or economically viable. We have been blinded with studies and reports from various sources which purport to support EirGrid’s case that an overhead line (OHL) 400kV interconnector is the only show in town. They all say that undergrounding of the project is not the optimum solution.

Following a joint report in 2004 by the Commission for Energy Regulation and its NI counterpart, the CER Director of Energy Networks confirmed in March 2006 in writing to EirGrid that the 400kV line was justified on the basis of both its higher energy transfer capability and its ability to be upgraded in the long run more practically and economically. This is when the decision was made to have 400kV as the optimal transmission. It is implied that this was to be an overhead line. What followed thereafter was a litany of reports commissioned by EirGrid to justify this decision.

It is factually wrong for EirGrid to claim that the decision to choose 400kV was arrived at after considering all the reports and industry standards that are prevalent in electrical power transmission. The decision had already been made in March 2006 prior to the published dates of all these reports used by EirGrid that have formed the grounds of their decision to construct overhead 400kV AC transmission line.

EirGrid has considered using an underground DC interconnector. In their evaluation their published conclusions did not justify this as being a potential solution for the building of the project. It did not consider the most up-to-date state of technology available in DC transmission capable of providing an underground DC interconnector now or in the near future.

For example, the recently commissioned 65km interconnector from Spain to France through the Catalan Pyrenees exploits new technologies in creating a 320kV 2000MW underground transmission. This is inclusive of having to drill a tunnel of 8.5km through the mountain and all at a cost of €700 million. The HVDC link was built as a joint venture between the French and Spanish grid operators RTE (Paris) and REE (Madrid).

The very fast control and protective intervention capabilities of the power converters provide for a high level of stability in the transmission system, which primarily serves to reduce grid faults and disturbances in the three-phase AC network. This significantly increases supply reliability for utility companies and power customers.

Mr Traynor continued: “I would have thought that many of the perceived technical problems that EirGrid have published about creating an underground DC solution for the North-South Interconnector are answered, or at the very least greatly reduced, by the employment of new technologies in this now commissioned France-Spain interconnector. There is also a Norway-Germany interconnector at an advanced stage.”

  1. EirGrid’s commitment to analysis of undergrounding other projects.

Grid West Project

On the 21 July 2015, EirGrid published details of underground and overhead options for the Grid West project, as outlined in its report to the Government-appointed Independent Expert Panel. The Grid West report sets out, in detail, the technical, environmental and cost aspects of three technology options:

  • a fully underground direct current cable;
  • a 400kV overhead line and;
  • a 220kV overhead line with partial use of underground cable

Grid Link Project

Eirgrid has confirmed that the original proposed overhead powerline from Cork to Kildare will not go ahead. An Independent Expert Panel said that the company is more likely to use a ‘regional model’. This would involve the strengthening of the existing infrastructure. It meets the needs of the project without building new large scale overhead infrastructure, according to the company.

EirGrid’s regional option alternative uses a technology known as ‘series compensation’. This would be the first time it will be deployed on the Irish transmission grid. It is an advanced, smart grid technology that will enable more power to flow through existing lines, and so does not require new 400 kV overhead lines.

The East-West Interconnector (EWIC)

The EWIC, which links the electricity transmission grids of Ireland and Great Britain, has been voted ‘Engineering Project of the Year’ by the Irish public in an online vote in the fourth annual Engineers Ireland excellence awards, in association with ESB. At 264km in length, some 187km of which is beneath the Irish Sea, the EWIC transports energy from a converter station in Co. Meath to North Wales. It is the largest voltage-sourced conversion scheme currently in operation in the world.

Fintan Slye, chief executive of EirGrid, said the interconnector was a key enabler towards meeting the ambitious target set by Government to generate 40% of electricity demand from renewable sources by 2020. It is the largest project of its kind to be undertaken in Ireland. He said: “The benefits to the community are immense and the boost to Irish competitiveness has meant that jobs that could have been lost to other countries have remained at home”.

  1. Upkeep and Maintenance Cost Effectiveness

Grid resilience is increasingly important as climate change increases the frequency and intensity of severe weather. All overhead transmission lines are exposed to more risk to extreme weather conditions as compared to correctly installed underground cabling. Underground cabling has an enhanced protection to weather events and affords significantly reduced risks of power transmission failure. Modern underground cables also offer superior performance characteristics and lower losses in bulk power transmission. Underground cable and its associated technologies can also enhance national security by bolstering the nation’s defences against cyber-attacks and terrorism.

  1. Future expansion capability

Because connection of wind farms, solar farms and other renewable forms of energy offers so many challenges in providing bulk power transmission and its intermittent mode of generation, DC power transmission and its associated DC convertor stations is largely becoming the preferred methodology. In addition, future connections by Ireland to any part of the European Grid system will necessitate the use of DC undersea cables with the associated DC Convertor stations to transmit and receive power from the European Grid system. As time elapses, and the investments increase across Europe in this preferred technology, we will find ourselves in a good position if we make the correct decisions on our current project like the North-South interconnector.

  1. What is the best option for all?

Any professionally designed and costed project of this magnitude would evaluate all the options and methodologies that could be used to provide its construction. It could then be objectively demonstrated the advantages and disadvantages of each option, the associated costs, their negative and positive impacts on the countryside, property, economy, environment and society. When options are discarded without such scrutiny, the project suffers because potential innovative technologies are not considered, cost savings may not be realized and the nation may get an inferior product which may not be fit for purpose or obsolescent in a few short years. Smart economies and smart businesses do not make these mistakes!

Undergrounding has not been scrutinized as yet in this manner and certainly not in the public arena for this project. It should be properly assessed and with the advancement of new cable technology and groundbreaking projects across the world, there is ample information and evidence available to actively consider this alternative.


Mark Norton EirGrid’s Network Planning Manager explained in response that the North/ South interconnector was sized correctly. He said it was designed with a 1500MW capacity in line with the company’s statutory obligations to develop a sustainable solution. This point was reinforced by the Commission for Energy Regulation and the Single Electricity Market committee.

He said similar projects across Europe were designed to transfer more power than what the actual network could supply. This additional capacity was designed to allow for intermittent nature of renewable energy and to develop solutions that are sustainable and therefore can accommodate future growth.

Mark Norton showed a table comparing nine projects of common interest. It detailed the designed capacity of a project and the corresponding capacity the grid has to transfer. The table showed the proposed north south interconnector had a grid transfer capacity of 73% – the highest of all the projects.

EirGrid put a huge amount of time and effort into assessing alternative technology options. This included the commissioning of independent reports into undergrounding and consideration of government expert reports, he said. Mr Norton added that after considering all this information and technology developments EirGrid believed the overhead line proposed was the best solution for this project.

Jarlath Fitzsimons SC for EirGrid replied to comments by a lawyer for the NEPPC about environmental impact assessments. He said recent case law indicated that an assessment of alternatives by the developer was not required. He said the EIS they had provided was more than adequate. There had been more than adequate consideration of route options by the developer and in preparing the planning application clear reasons had been given for the choice.


Nigel Hillis of CMAPC asked Aidan Geoghegan of EirGrid about the costs of the project. The Project Manager confirmed that the construction cost was €286m for the whole route and allowing for landowner compensation. But this did not include a figure of €8.7m for what the company describes as ‘community gain’. Under the local community fund EirGrid pays €40,000 a kilometre for communities near 400 kV pylons and sub-stations.

Asked about the merits of underground technology instead of overhead lines, Mr Geoghegan pointed out one of the reasons EirGrid had proposed the overhead option was because it could take 25 days to repair a fault on a high voltage DC underground cable system.

Colin Andrew for the NEPPC said apart from capital expenditure the costs of the project had never been broken down sufficiently. He said the costs must include the impact on the local community, which was resolutely opposed to the development, as EirGrid was well aware.

Following a question from the presiding inspector, Mark Norton of EirGrid gave an explanation of some of the technical terms that had been raised. But Nigel Hillis suggested what was needed was for Bord Pleanala to arrange to bring to the hearing the three members of the International Expert Commission who had drawn up a report on undergrounding opt

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