I'm afraid that this is a bit of a badly-curated wander, where I mostly just popped out to find out a little of the history of Underfall Yard and poke around the various open workshops, and, in hindsight, really didn't take pictures in any kind of coherent order. So there's a lot of pictures, but they don't really tell the story that, in hindsight, I seem to have been trying to tell, of the unusual electrical substation in Avon Crescent, the Bristol Electricity that predates the National Grid but is still in use, the history of the hydraulic power house... It's a bit of a mess.
But I suppose sometimes these wanders—always chronologically presented in the order I walked and took photos—simply will sometimes be a bit of a mess. Let's hope you still get something out of it, anyway...
It's very hard to get a decent look at this building. This is the top half of the back of it.
The poor place is much-neglected.
This building is, or was, an electrical substation. I heard an unconfirmed rumour that the building itself is now actually empty, and that the entire substation guts are now in these boxes. I have no idea whether that's true or not.
Here we've turned the corner onto Avon Crescent to see the front.
You can see this once apparently bright and airy building has had every window bricked up.
I understand that something in or around this building still supplies the odd electrical requirements (specifically, 360V "Bristol voltage") for some bits of Underfall Yard, which is our next stop, so more about that when we get there.
While it's not a listed building, is is notable: it's one of the earliest reinforced concrete buildings in the UK, apparently, construction starting in 1905. I assume it was up by 1907, as that's when Undefall Yard installed their electric pumps.
This oddity of history predates the National Grid and was originally fed from Feeder Road power station (well, Avonbank, on Feeder Road, to be precise. We've seen a bit of that history before, as a line marker for the line from Portishead to Feeder Road.) It was connected to Feeder Road by 1906, with a 6,600V line.
I've added a couple of historic views of the building as the next two photos in the wander, but I'll also pop this link to a Loxton drawing of the Avonbank electricity works, 1908 here.
Via this Tweet and taken from KYP Bristol, showing the interior with a couple of Westinghouse rotary converters and a Peebles-La Cour motor converter, assuming this picture ties up roughly with this 1908 Institute of Mechanical Engineers' visit to works.
You can see a picture of similar Westinghouse converters to the two at the back in the Wikipedia rotary converter page and a Peebles converter that looks very similar to the one in the foreground on the cover of the Peebles motor converter catalogue in the sidebar of their entry in Grace's Guide. I'm guessing the additions on the ends of the Westinghouse converters were for different voltages? A rotary converter is basically a motor connected to a dynamo, so extra dynamos with different windings would give you different voltage outputs, I suppose, but I know very little about power generation.
And here's the Loxton picture of the exterior, from the Bristol Libraries collection. Seems such a shame to have bricked up those lovely windows.