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 Often irrigation systems are out of date and are in need of replacement to incorporate new technologies and updated knowledge.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 244 ha and is divided into three sectors that are serviced by five pumps. Although there are five operational pumps, only four analysis’ are reported as Pump four was unable to be obtained due to the drought experienced during the audit.
Pump one services 55 ha and has been experiencing operational difficulties noted as severe pump cavitation, slow system fill on start-up, evidence of iron oxide issues and some pipe fitting irregularities. This pump provides water to a high-pressure gun and low-pressure flood irrigation. Pumps two, three and four are interconnected by an underground mainline which supplies water to 139 ha. Pumping distances and efficiency issues associated with friction means that the best operational procedure in sector two is to irrigate the area closest to each pump. Pump five draws its water supply from the Bundaberg surface water supply scheme and has a system design that manages distribution pressure via a manual check valve. Unfortunately, this is a highly expensive way to achieve this outcome. Pump four is located on a gully dam within grazing land attached to the sugarcane operation. The pumping unit is relatively new and is fitted with VFD and connected to Tariff 33.
Energy consumption from the site showed that a total of 426,071 kWh at a cost of $91,008 was used during the 2018-2019 period. A recent energy audit showed how improving the current systems can lead to energy and cost savings. The recommendations explored in the audit included:
- The installation of VFD to pumps one, two, three and five.
- Conversion to Tariff 33 at pumps two, three, and five.
Table 1. Energy savings from audit recommendations
||Annual Energy Savings (kWh)
||Annual Cost Savings ($)
||Emission Savings (tCO2-e)
||Capital Cost ($)
||Payback Period (years)
|Install VFD in 4 pumps
|Change 3 pumps to tariff 33
The addressing of the operational issues related to iron sludge restrictions and replacement of suction pipe fittings at pump one will improve the functionality of the pumping system and improve performance. Repairs and maintenance or replacement of the Southern Cross pump will further enhance the functionality and performance of the pumping system. Energy demand and consumption will decline with the introduction of VFD technology which will manage the system operating head (m) to meet the specific target demand. Conversion to Tariff 33 is recommended to maintain lower energy cost over the longer term.
The combined effect of all the recommendations will reduce the annual enterprise energy demand by an estimated 98,031 kWh saving $37,471 to yield approximately 18,000 tonnes annually.
By installing the recommendations in the audit, the business could reduce energy consumption for pumping by 25% and costs by 43%, with carbon emission savings of 84.1 tCO2–e per year, which will enhance the profitability and productivity of the farm.
Table 2. Pre and post audit energy consumption, costs, and energy productivity savings
|Energy Consumption (kWh)
|Energy Productivity (kWh/ha)
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 onsite.
An energy auditor will review your past energy bills, your equipment and the way your business operates. They’ll show you where you’re using excess energy and explain what you can do about it. Find out about what’s involved in an energy audit HERE.
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The Energy Savers Plus Extension Program is delivered by the Queensland Farmers Federation with support and funding from the Queensland Department of Energy and Public Works.