Bernadette Kearney recalls the day she and her choir sang in the heart of Turlough Hill

To sing beneath a lake in the belly of a mountain, that was our mission.  

The cavern stretched before us like a big gaping mouth in the face of the mountain ready to swallow us up.    

The red carpet running through it resembled a giant tongue as we slowly walked along it, magical atmospheric lighting strategically placed guided us on our way.  

Stalactites dripped from the tunnels roof like little daggers. We walked further and further down into the depths of the cavern, water oozing lazily through the arched roof just to remind us that there was a  gigantic lake hovering somewhere above us. There was no going back.  

We giggled and chatted as we made our way towards the stage, set up in the bowels of this man-made colon. Where were we? We were in the belly of the first and only hydroelectric station ever built in Ireland called Turlough Hill deep in the beautiful Wicklow mountains.

What were we doing here? We were about to perform in a concert appropriately named ‘Concert in the Cavern’. The concert was to celebrate the 40th anniversary of Turlough Hill and its critical role in meeting the energy needs of modern Ireland.
Now for the science bit. Turlough Hill was created to meet with the rapidly growing demand for electricity in Ireland in the late 1960s. A rapidly responsive pumped-storage hydroelectric station. The location was chosen in the Wicklow Gap in the Garden of Ireland because of a natural corrie lake, Lough Nehanagan, which would become the lower reservoir and there was also a suitable site on a nearby mountain where an artificial upper lake could be built.  Construction began in 1968 and was completed six years later.

A massive underground chamber in the granite mountain was drilled out to house the main station so that it would be hidden from view and would not blemish the stunning Wicklow scenery. This chamber is the same size of a small cathedral. Tunnels were drilled through the rock connecting the station and upper/lower lakes.  

So when there is a surge in the nations electrical requirements, say at 6p.m. on a cold January evening, cookers are turned on, lights are ablaze and the nation is sitting down to watch the 6 o’clock news, this powerful station kicks into action and starts pumping like mad to generate huge amounts of electricity to stop your lights from flickering!  
 It does this by releasing water from the upper reservoir through the four turbines in the belly of the hill and into the lower lake.

Likewise when all goes quiet again, and the nation sleeps, the turbines go into reverse and send water back through pipes to the upper lake ready for the next surge.  Wind energy is also used to pump the water back to the upper lake completing a virtuous cycle.
Well back to the Concert. Our choir, the Wicklow Choral Society, waited patiently on the seats provided behind the stage, looking at the big plasma screen put there for our convenience to watch the earlier acts. The guest of honour was Turlough O’Riordan. This is strange but true; Turlough means ‘dry lake’ in Irish but he was not called after Turlough Hill, the hill was called after him.

His father, the late Dermot O’Riordan, Deputy Chief Civil Engineer with E.S.B., whose vision this ingenious station was, called it after his son.

The Clare Memory Orchestra performed first with their beautiful mix of traditional and classical music and filled the cavern with their haunting sounds. Martin Hayes, an All Ireland Fiddle champion and Dennis Cahill a master guitarist performed a spell binding and fiery performance. Eventually it was the turn of the Wicklow Choral Society to pop up on stage and perform in this the most unusual of venues.

Well we sang our little hearts out under directorship of our choirmaster Frank Kelly. At the end of our performance we had the added privilege of listening to Paddy Maloney of the Chieftains who made an impromptu appearance on the stage. Oh happy days!
So if you’re ever passing on the small winding road over the breathtaking drive across the Wicklow gap, from Glendalough to Hollywood, and you look carefully, you might see a strange looking mountain with a flat top. This will be your only clue to this massive feat of engineering – a testament to the belief that nature and man can indeed live in peace and harmony.