Pumped storage plant for peak load. If there is a shortage of water at a particular plant location, and if it is possible to have ponds at the head water and tail water location, the water after passing through the turbine, may be pumped back from the tail race pond to the head water pond. During times of peak load, Water is drawn from the head water pond through the penstock to operate the turbines,and during the off peak period, it is pumped back to the higher level. The pond capacity should be suitable for a 4 to 10 hour supply of energy at peak load time. A general arrangement of a pumped storage plant is shown in fig. 7.13.