The sugarcane cropping lands consists of 101 ha and is serviced by three pumps. Farming requires constant decision making to maximise production and profit. Crops are often rotated due to season changes, weather variations and higher value products though sometimes the systems in place are outdated and are in need of an upgrade.
The current irrigation system is run by two electric pumps supplied from ground water bores and a diesel pump located on a tail water collection dam. Irrigation methods on the property include high pressure travelling gun and low-pressure furrow (flood). Pump one draws from a borehole depth of 5 m and delivers water via 700m of 150 mm underground mainline. Pump two draws from a depth of 4 m and delivers water via 1200m of 150 mm underground mainline. The third pump (the tail water diesel pump) was not included in this audit as its utilisation is sporadic. Pump two presents the most opportunity. Whilst it is flood prone like pump one, the distance to high ground is only about 100 m where the Ergon grid is located which provides an opportunity to substitute grid energy with solar PV.
A recent energy audit showed how improving the current systems can lead to energy and cost savings, the recommendations explored in the audit included:
- Install two Variable Speed Drives (VSD) on pump one and two.
- Install 30kW solar PV system to existing pumping system (savings calculated post VSD installation).
Table 1. Energy savings from audit recommendations
||Annual Energy Savings (kWh)
||Annual Cost Savings ($)
||Emission Savings (tCO2-e)
||Capital Cost ($)
||Payback Period (years)
|Install VSD in 2 pumps
|30 kW Solar Pump
Energy consumption from the two pumps sites showed that a total 98,521kWh at a cost of $19,895 was used during the 2019-2020 period. Pump one operates a travelling gun irrigator which services around 30 ha of the total harvested farm area. Installation of a VSD on pump one will reduce the operational cost of the annual irrigation program by an estimated $2,706, while it is also estimated that the energy cost for pump one will decrease by 25 – 30% once all audit recommendations are made. Pump two supplies water to a travelling gun irrigator and furrow and services around 40 ha. Like pump one, the installation of a VSD will greatly reduce irrigation costs, saving $12,838.
Energy demand will decline as VDS technology will better manage operational head factors, while the inclusion of a 30kw solar PV will also greatly reduce costs and energy consumption. It is estimated that a further $16,465 can be saved by installing a solar PV. The farm has recently completed works to transition from obsolete farming tariffs and has moved to T33.
By installing the recommendations in the audit, the business could reduce energy consumption for pumping by 63% and costs by 96%, including productivity gains, with carbon emission savings of 38.2 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.
See our range of agricultural energy efficiency case studies HERE and Subscribe to our bi-monthly energy e-news HERE
If you have any energy efficiency related questions for the team get in touch at firstname.lastname@example.org.
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.