PUNCH Consulting Engineers was tasked with preparing a Civil and Structural Engineering Due Diligence Report for the proposed 38kV cable route at Lisheen III for Brookfield Renewable Energy Group. This report assessed the available environmental, geotechnical, planning, utility, and hydrological information relevant to the route. The report documented how this information impacts the proposed route and highlighted areas of conflict, potential issues, and necessary site investigation work to allow for a robust and cost-effective design solution for each of the crossings encountered along the cable route.

The cable route extends approximately 12 kilometres from the Thurles 110kV substation in Ballygemmane, Co. Tipperary, to the Lisheen III Wind Farm in Derrygreenagh, Co. Kilkenny. Elevations along the route ranged from 110mOD to 135 mOD.

The cable will be installed in trenches filled with granular material. However, at two crossing points of tributaries of the River Drish, the trenches will be shallower, and the cable ducts will be required to be encased in concrete. Approximately 50% of the route passes through peat beds, where a geotextile membrane will be incorporated into the trench backfill.

PUNCH recommend considering directional drilling at two specific locations along the route: the high voltage crossing in the roadway near the entrance to Lisheen Mine, and the bridge and rail track crossing the bog north of the Lisheen Mine entrance.