http://www.gilkesenergy.com/project/Broom I spotted this beside the A9 and looked up the data. It says it can shift 400 litres per second, which is 400 kg per second. The head is 163m. So say that 400kg falls through 163 metres. It loses 400 x 9.81 x 163 = 639kJ of gravitational potential energy. I'm tempted to say that this equate to 639kW because of the per second bit but am mindful that it must take longer than 1 second to fall down the 2km pipe. On the other hand, this may be confusing energy and forces methods. It can operate at 483kW which would give an efficiency of 76%. Need to think about this one.
