When you hear or read the words water power like me you probably think of hydro but this week I learnt that Scottish Water are putting in a large PV array to power the water treatment works that provides my water. In fact part of this story does involve more conventional water power in that I believe they are putting a hydropower scheme nearby as well for the same purpose. You may also have heard of the floating PV array being put in at a water treatment works near London. This is also going to be used to power some of the water treatment there. Water companies are also putting in anaerobic digestion plants and wind turbines to power sewage treatment plants.
There is an important point here. The array (ground mounted) in Edinburgh is going to be 250kWp, the floating array at the Queen Elizabeth II (QEII) reservoir near London will be 6.5Mwp. Neither is meeting the entire energy needs at their respective sites. The water we use at a domestic scale uses a lot of energy. This falls into two parts, treatment and getting it to us. The treatment (by which I also mean sewage treatment) takes a lot of energy but any pumping probably takes even more. My understanding is that Edinburgh’s water supply from the reservoirs is entirely gravity fed. However sewage and water treatment obviously still takes a lot of energy. It really is worth conserving water for its energy use alone and switching that tap off when you clean your teeth.