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A sugarcane farming enterprise located in Moore Park Beach could benefit from a recent Energy Savers Audit. Farming requires constant decision-making to maximise production and profit. Often irrigation systems are out of date and are in need of replacement to incorporate new technologies and updated knowledge.

The total area of cropping lands consists of 63 ha and is serviced by one pump operating two irrigation systems; a high-pressure travelling big gun and a low-pressure surface furrow system. The high-pressure system irrigates a significant proportion of the farm with an average energy use of 530 kWh per ML of water pumped. While where the topography of the land allows, a low-pressure furrow irrigation system is used, as the energy use is much less at around 166 kWh/ML of water pumped. Unfortunately, this furrow system can only be used on a small section of the farm due to the lay of the land and soil types.

Although is it also noted that the annual energy utilisation by the irrigation pumping systems is directly related to the impact of seasonal rainfall on the daily moisture demand of the sugarcane crop. During the energy audit, the farmer switched from Tariff 66 to Tariff 33. This adaption has seen a reduction in energy costs relative to the volume of energy consumed.

Energy consumption from the pump site showed that a total of 68,851 kWh at a cost of $ 17,756 was used during the 2018-2019 period. A recent energy audit showed how the replacement of the pump, motor, and installation of a Variable Frequency Drive (VFD) at the main pump can lead to energy and cost savings.

Table 1. Energy savings from audit recommendations

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The replacement of the pump and motor and the installation of the VFD at the pump will lead to a significant reduction in energy use and cost and will provide the potential for sustainability of current levels of high productivity. The new motor will improve efficiency by 4-5% and the new pump will feature more efficient design and task suitability which is estimated to improve efficiency by about 18% when operated in the travelling gun high-pressure mode, and 10% when operating in the flood low-pressure mode. Inclusion of the VFD will manage friction head in the mainline pipe by managing the correct pressure relative to the operating distance from the pump. The installation of a VFD will also remove the need to change drive belts to adjust operating speeds when a lower pump speed is required for furrow operation. This can be a very dangerous task when the pump is hot, so the VFD will create a much safer operating environment.

The farmer proceeded with the implementation of the pump upgrade with VFD, with potential energy consumption savings of 48%, costs savings of 57%, and carbon emission savings of 26.5 tCO_2-e per year. Actual savings will be updated once the measurement and verification process is complete.

Table 2. Pre and post audit energy consumption, costs, and energy productivity savings

An energy audit is a good investment

An energy audit is a great first step in moving a business towards a more efficient future by reducing energy use, costs, and carbon emissions on site.

The Energy Savers Plus Extension Program was delivered by the Queensland Farmers' Federation with support and funding from the Queensland Department of Energy and Public Works.