Saturday, September 27, 2025

Turlough Hill Transmission Lines

Twin 220 kV lines crossing the mountains from Turlough Hill hydro station. © Eugene Brennan

One of my cycles back in mid-August (the long days of summer seem to be a distant memory now) was from Kilcullen to within a few miles of Turlough Hill. This is the location of Ireland's only pumped storage power station. When there's a surplus of power which the grid can't use, pumps at the station send water to an artificial lake located on top of the mountain. Once there's a demand for power, the motors and pumps switch function and become turbines and generators, the turbines driven by water as it rushes down through penstocks (large pipes) to a natural lake, located at the base of the mountain. Turlough Hill power station is net inefficient (power out is less than power in due to losses in the system). However it acts as a buffer on the grid, being capable of supplying power within a short space of time, unlike conventional thermal power stations. Battery energy storage systems (BESS) will replace this type of system in the future, to cope with the erratic nature of renewable energy sources such as solar and wind generation. Although getting planning approval for BESS facilities can be difficult (as we saw locally), it's probably a lot easier than getting permission for a facility which would end up "ruining" a mountain as some would see it, or planning permission to flood a valley for a hydro station. 
My route. It's roundabout to avoid very steep hills and busy roads. © Eugene Brennan
 
When I'm heading for Turlough Hill, I turn right just before the left turn for Valleymount on the Hollywood-Glendalough road. This road is a cul-de-sac that runs along the King's River for around three miles before becoming a track that meanders through open landscape (with nice scenery) and forest. It's possible to cycle for another three miles or so over logging trails before rejoining the road to Glendalough, near the bridge over the King's River.  Twin 220 kV transmission lines from Turlough Hill run parallel to the King's River, on their way to Dunstown 400 kV Substation and Maynooth 220 kV Substation. (One of the transmission lines from Turlough Hill and another from Great Island Power Station in Waterford cross Boleybeg Hill near Branncockstown on their way to Dunshane substation.) These are transmission lines, carrying power long distance throughout the country. Distribution lines carry power locally, to and from smaller substations that serve towns and villages.
Forestry trail that runs parallel to the Kings River. © Eugene Brennan

Mountain rowan. © Eugene Brennan

The 220 kV transmission lines run along the cul-de-sac road that branches off the Hollywood-Glendalough road. © Eugene Brennan

Twin 220 kV lines crossing the mountains from Turlough Hill. © Eugene Brennan

Trail through forestry. © Eugene Brennan