OK I must confess that I haven't actually done the whole tour thing here, but having worked inside…read morethe mountain for a few days I can appreciate how awesome a thing it is.
Firstly, let's talk about the visitor centre and cafe. A great place (in fact the only place for miles) to grab a snack or a light lunch. Try to get in when there isn't a tour about to happen as they get very busy and the service gets pretty slow. The staff are all very friendly and cheery though, and you usually get a good bit of banter with them. There is free Wi-Fi too, although it can be somewhat variable at times!
Not for vegans - there is nothing on the menu suitable for the vegan appetite, the closest veggie option is a cheese toastie. If you're lucky they might have a veggie soup on offer, but make sure you check as even the lentil soup had meat stock in it when I was there. That's the only reason I'm giving the place 4 stars, it should otherwise be 5.
There are a number of exhibits and photographs telling the story of the construction of the dam and power station, plus the inevitable gift shop to browse while you are waiting for the next tour bus to depart. If you're the hillwalking sort, they can also advise you on the route to take to walk up to the dam above - but it is pretty steep, be warned!
The mountain - Visitors are driven into the heart of Ben Cruachan in wee minibuses. There's a sliding security gate at the mouth of the tunnel, and then a tunnel that's nearly a mile in length descending into the heart of the mountain. You feel like you are entering a super-villain's lair in a Bond movie, a feeling that is reinforced once you get up to the viewing gallery and see the whole expanse of the massive turbine hall. I'm really surprised that it hasn't already featured in a movie as it would be a perfect location for any spy film!
There are four massive turbines that can generate 440MW of power on demand. The bits you can see is only the very top of these enormous machines; like icebergs there is much more below the surface (another 3 or 4 levels in fact). Cruachan is a 'black star' station, which means it can be used to re-start the entire national grid if everything else went off for whatever reason. It was the first such hydro scheme to be constructed, and because the turbines can generate electricity almost instantly by simply opening the valves that let the water in from the dam above, it's ideal to provide increased capacity at peak times. During the night, the turbines can be reversed, to pump the water from Loch Awe back up into the reservoir.
Check out the wooden mural by Elizabeth Faulkner on the wall - this tells the legend of the sacred well on the mountain that was guarded by the Cailleach, the crone goddess of the mountains. She controlled the flow from the well by rolling a boulder over it, but one night she fell asleep and the well overflowed, causing Loch Awe to fill up and burst its way through the hills, creating the Pass of Brander. The rest of the mural commemorates the 4 engineers who were in charge of the project, the 15 tunnellers who died during the construction of the turbine hall when the roof collapsed (a total of 36 workers died overall), and the switching on of the power by the Queen in 1965.
Awesome, amazing, atmospheric, inspiring. Well worth stopping off for.