You may have noticed if you have walked past our turbines or looked at the live data feed on our website that we have only been running one of the two turbines for half of May. This is because we have had a bearing failure on Turbine 2 (Sophie), the one furthest away from the View Island bank.
We have an automatic condition monitoring system fitted to the turbines and, early on 13th May, we received a Red alert alarm for the bearing that supports the top end of the Archimedes Screw. Spaans Babcock, who made and installed the turbines, came straight to site, and told us that we needed to shut that turbine down. The bearings should last 10-15 years so the failure was not expected. Spaans had to order some spare parts, and then arranged to come and replace the bearing, under warranty, starting on 30th May. The turbine started running again on 1st June.
In order to replace the bearing we had to remove the water from the outlet channel of Turbine 2, which we had not done before. This was achieved by lowering wooden planks – stoplogs – into the grooves at the end of the channel and sealing the wooden wall this made with a tarpaulin. Once this was done we were able to pump the water out of the channel. After Spaans had completed their work we carefully removed the stoplogs, allowing water back into the channel.
Although both turbines are now running again the water level in the River Thames is now low which means that we are not always able to generate full power. The Environment Agency requires Reading Hydro to shut down when the river levels are below an agreed ‘set level’ to make sure there is enough water for navigation. When the upstream level gets close to the set level, power generation is reduced.