What is Pondage?
The Power demand of hydroelectric power plants fluctuates with time. If the storage reservoir of water is situated away from the plants then a small pond is built near the plants to meet the hourly changes in demand. This small pond near the plant is known as Pondage.
Since the load on plants vary with time, during the low demand of load excess water is stored into Pondage and when load demand increases then stored water into Pondage is used to supply to plants to overcome the increase in demand.
The Capacity of the Pond should be sufficient to overcome hourly changes for 24 hours. if the weekend load conditions are very different from weekday conditions, the capacity of the pond should be determined from a study of load and streamflow for one week.Further, the studies should also take into account the seasonal load variation.
Advantage of Pondage
By Installing Pondage near the Hydro-Electric Plant, it has some advantages
- it increases the efficiency of the plant.
- it stores the excess water during a low load period.
- it is used to meet the instant requirement of load
Disadvantage of Pondage
Disadvantages of Pondage are given below
- It increases the initial Investement of the Plant.
- It requires extra Civil Work
- Extra manpower is required to operate and its maintenance
The Capacity of the Pond can be determined in a manner similar to that for determining the capacity of the reservoir.However, the demand, in this case, is represented by the chronological load curve.it is evident that the necessity for Pondage arises because the plants mostly work at a load factor of less than 100 percent. if it is possible to operate a hydro plant at 100 percent load factor then there is no need for Pondage.