Mr. Fintan Slye:

There have been several detailed analyses of undergrounding the North-South interconnector. In 2009, we published a detailed, route-specific analysis of undergrounding by the international company, PB Power. That was updated in 2013. The Government appointed an international expert commission of three who examined the case for and cost of undergrounding it. The independent expert panel appointed by the Minister concluded that in all material respects undergrounding had been examined to the same extent and level of detail as was being proposed for the Grid Link and Grid West projects. All of that analysis has been done for the North-South project. It has been publicly available and has been debated publicly, including with this committee.

The Deputy mentioned the multiples of the cost as being 1.57 versus six times. I take it the 1.57 is from the comparison of options for Grid Link in the recent strategy. For different projects different technology solutions are appropriate and they require different capacities of interconnector. For Grid Link the proposed underground scheme is 700 MW, but for North-South a 1,500 MW scheme is needed. Therefore, the comparison is not like for like. The 1.57 is based on a 700 MW scheme for the Grid Link project. There is still a band around that €800 million to €850 million as we are still involved in the engineering and detailed design of that. With the delivery of the east-west interconnector, we have a lot of experience of the costing, engineering and delivery of these high-voltage direct current, HVDC, projects.

The higher cost multiple comes from our detailed engineering analysis of delivering an underground solution for a North-South connector and from the PB Power report where the multiple was approximately five. That is based on a detailed engineering analysis, component by component and route specific, which is all documented and set out in the PB Power report, which was updated in 2013.

The other number often cited is a multiple of three. This comes from the international expert commission appointed by the Government. That multiple was not derived through an on-site engineering study, but through comparison with a range of projects around Europe. The commission carried out an international benchmarking exercise - some of the commission worked closely on those projects and I expect it was good information - and its conclusion was a factor of three.