The audit recommended the replacement of a 50kW pump which is over-sized for the duty requirement which would give an energy saving of 56% and a payback period of around 8 years. In addition, changing tariff and switching pump operation to off-peak hours would save an additional $1,200 per year. Annual emission savings have been estimated to be 3 t CO2-e.
The large apple orchard is located at Cottonvale in the Southern Downs region of Queensland. Irrigation is via low-pressure sprinklers fed either from a single electric pump or from two diesel pumps. The water supply around the farm is managed by using a series of valves to configure water flow to the desired area. The main irrigation period is from September to April when pumping is undertaken during peak periods for an average of one hour per day.
The owner is not planning to implement the audit recommendation due to the long payback period. Replacement of the pump would be subject to equipment failure. The proposal to review the tariff pricing structure remains under consideration as ongoing use of the electric pump is subject to several factors including rainfall and future irrigation requirements.