The Kourarau Power Scheme consists of two small power stations: Upper Power Station B and Lower Power Station A. Each station is fed by a small artificial reservoir formed by the damming of Kourarau Stream. Between each reservoir and the associated power station are sections of pipeline and penstocks that take water from the reservoir to a power station. Water from the Lower Power Station is discharged back into the natural channel of the Kourarau Stream.
For a description of the Kourarau Power Scheme click here.
Contribution to the National Grid
The Kourarau Power Scheme has an installed generating capacity of 1100 KW, however, generation rarely exceeds 900 KW. The scheme was designed to meet the generating needs of some 235 consumers. The Kourarau Power Scheme does not feed directly into the national grid. The electricity is distributed throughout the Wairarapa area.
KEY FACTS
| KOURARAU POWER STATION | |
|---|---|
| Year Commissioned |
Station A - 1923
|
| Total Capacity |
Station A and B - 1100KW (generation rarely exceeds 900KW). |
| Generation Units: |
Station A - Boving twin disc pelton wheel turbine driving and electric 700 KW generator.
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Challenges faced in operating the scheme
Limestone accumulation
As a result of the limestone geology, water in the Kourarau Stream contains high concentrations of lime. The lime accumulates on the inside of the pipeline and penstocks that feed the Lower Power Station. This build-up reduces the volume of water able to be conveyed, which in turn affects the efficiency of the scheme. The lime build-up requires removal every two or three years.
Desedimentation of the lower reservoir
During flood events sediment is transported into the Upper and Lower Reservoirs. Over time this sediment accumulates and can become an issue for power scheme operation and therefore, generation. There is no practical way of removing sediment from the Upper Reservoir. However, sediment is removed from the Lower Reservoir by drawing the reservoir down until it is empty, then a sluice gun is used to dislodge sediment from the bed and banks of the reservoir. Sluicing occurs whenever regular inspections reveal that sediment has built up to a level where it is beginning to inhibit flow through the intake to the Lower Power Station. This activity occurs every four or five years.
Other maintenance activities include:
- clearing intakes, drains, pipes and culverts
- replacement of worn components
- weed clearance
- trimming of overhanging vegetation
Genesis Energy has several resource consents to operate and maintain the Kourarau Power Scheme.