We walked up to the catchment pool at the top. From the map, I think that there is a 120m drop between the upper pool and the generator. It is said by sources I have found to be a 1.7km pipeline. It starts with the blue section on the left of the photograph but I couldn't find any other evidence of it near the generator hall. But I did find the outflow back into the river just below the generator.
It's nearly 3 decades since I studied fluid mechanics. I have been trying to figure out how to calculate the likely fluid flow rate in the pipe but the equations are hard. I hope to post more about this later. However, I did find some very interesting data on Capacity Factor. http://www.variablepitch.co.uk/stations/288/output/ It's interesting that the best it can manage over a month is to produce 50% of its theoretical maximum output. In other words, saying that it is 500kW is one thing but it can seldom operate at that power. It also clearly varies with the rainfall. It is so unobtrusive that it seems an excellent use of resources. It says it is not attached to the National Grid but I can only imagine that the houses are attached to make up for any shortfall when water levels are low.
