Individually designed turbines using the fall of the Canterbury Plains combined
with large flow to drive irrigation pumps directly and/or produce electricity.
Typically, water is diverted out of a scheme irrigation race into an elevated intake
canal and falls 3.5 – 7.2 meters through a crossflow turbine driving an irrigation
pump via a speed up drive. A tailrace below the turbine returns the water to the
main irrigation race. The smallest installation has a turbine mechanical power
output of 30 kW, the largest 240 kW. Output depends on the resource available
and the spray irrigation system demands.
Crosstech Engineering, a small privately owned Christchurch company, designs the
schemes and manufactures the turbines locally. Ten installations have been
completed since 2002 with one also generating electricity back into the national
grid. Further installations are underway.
Eliminates pumping costs with minimal ongoing maintenance costs.
Typical capital cost of $150 000 for $35 000 annual saving (120 L/sec output).
3 – 5 year payback.
No concern about electricity price increases in the future.
Reduces electricity and diesel consumption.
Harnessing local renewable energy resource with minimal environmental impact.
Multi purpose use of water rather than just for irrigation.
Facilitates the change from less efficient borderdyke irrigation to spray irrigation.
Potential for many more schemes on existing community irrigation schemes
throughout NZ, big and small and for direct pumping or electricity generation.
Excellent prospects for intergration into future community schemes such as
proposed Central Canterbury Plains.
Technology and experience easily transferred to harnessing streams/rivers and
for electricity generation.