On a normal day at Harlaw Hydro there is little excitement, water comes down, the turbine goes round, and we generate green electricity. In the background there is routine remote monitoring of water levels to try and maximise what we generate and a monthly greasing of bearings.
Last week was different. Despite having plenty of water we were generating in the low 60Kws rather than the 70kws and there was more noise than normal. With cameras to see and remote access to the controls actual visits to the turbine house are limited but Monday was the day scheduled for greasing and the system was not just noisy it was vibrating. Something was clearly not right. The power generated was reduced until the vibration stopped and our maintenance engineers were contacted.
We have a 20mm grill in the water tower to stop debris (and fish) coming down the pipe, • could this be partially blocked? • But where did the vibration come from? • And why was there a Heron standing beside our plunge pool?
Our engineers systematically checked the turbine, including removing the two inspection covers to allow them to inspect the runner (the part of the turbine that spins round and gives us the power). The runner was fine, as good as new, but what was that in the corner? A glove was put on and the body of a 5lb trout was fished out. The fish had been trapped round one of the guide vanes restricting and destabilising the flow to the runner, some how a small stick had also joined in. Fish removed, covers replaced and all now running perfectly.
The heron was disappointed.
Thanks to conscientious monitoring by our team and prompt action by Proterra (the firm that does our maintenance) all is well and no damage done. The addition of a microphone so that we can hear as well as see remotely is being considered.
Many lockdown days ago we thought that we might be free to meet in September but this is looking less and less likely, accordingly the board has decided to hold the AGM as a webinar, ie remotely over the internet. Members have been sent, papers for the AGM and will know that the date is Friday 26th June at 7.30pm. Details of how to join the webinar will be sent out nearer the time.
The Coronavirus, even with its slightly snappier title of Covid-19, has invaded almost every aspect of life but not quite all; when it rains the water still goes down the hill. In the last financial year mother nature has truly provided.
In line current restrictions the AGM will not be in June this year, it may be possible to hold it in September, that will be assessed during the summer.
On Wednesday 18th CEC closed the outer valve on the main tower as the first part of the annual dam inspection. Unfortunately the rod connected to the gate valve parted company from the worm drive mechanism that is meant to wind it up and down. This left the valve closed and Harlaw Hydro with no water supply. This morning (27th) the CEC blacksmith re-united the rod with its winding mechanism and we started generating again.
Those who have been watching the power meter will realise that we are only just generating electricity at the moment. Match the captions!
Harlaw + Water April 2016
Harlaw – Water November 2018
The ‘beach’ at Threipmuir November 2018
High and dry inlet to the Harlaw Upper Tower
High on the left is the concrete V at the overflow.
Who said the fishing season is over?
Upper Harlaw sans water.
Low water is not only unsightly and poor for electricity generation it also most importantly is dangerous. Low water exposes parts of the bank which may shelve quickly, as in Harlaw, and exposes very fine and soft silt, as in Threipmuir. A number of people, walkers and fishermen, have sunk into the soft, muddy silt and needed help to get out. One person went in to rescue her dog and ended up needing to be rescued by the Fire Brigade.
This weekend is Edinburgh Doors Open weekend and Pentland Regional Park are opening the doors to Harlaw Visitor Centre. A number of other local organisations will be there too, in particular their will be regular tours of the Harlaw Hydro Powerhouse. We’ll be there 11-00 – 15.00 on both days.
As many will know our first service has been a long time in coming, and has required plenty of patience and stubbornness, but on Monday our turbine received its first service. The major task is the lifting of the generator and the runner to facilitate a proper inspection; with the help of our new lifting frame this proved to be quite straight forward. The inspection yielded no nasty surprises with the runner almost as good as new after nearly 3 years of operation.
As you’ll see in the picture of the inspection cover all the brown water coming out of Red Moss and off the hills has left its mark with a fine but thick peaty deposit. We plan to pressure wash the inside of turbine casing and the lower part of the pipe work to clear this.