An energy audit showed how improving the current irrigation system can lead to energy and cost savings. The recommendation explored in the audit included install Variable Speed Drive on the irrigation pump to modulate pressure automatically at 200 kPa at the irrigation valve stations.
Energy Savers
Summary
The farm, near Mareeba, produces mainly bananas with water delivered to the plants via a sprinkler irrigation system. The farm is split into different sections for irrigation, with each section requiring between 12 and 18 hours of irrigation per week, depending on rainfall. There is one pump on-site which irrigates blocks of between 15 and 20 hectares at a time, and runs for around 5,300 hours per year.
Energy consumption is dominated by pumping and irrigation operations. The annual energy consumption for the site is 446,114 kWh at a cost of $90,430.
The site energy consumption consist of:
- One 75kW centrifugal pump that already operates on a variable speed drive.
- One 55kW centrifugal pump was assessed as part of the audit.
An energy audit showed how improving the current system can lead to energy and cost savings by investing $33,830 in order to install a Variable Speed Drive (VSD) on the 55kW irrigation pump to modulate pressure automatically at 200 kPa at the irrigation valve stations. This initiative would also involve removal of the primary sustain valve to enable pressure control via a variable speed drive and improve efficiency.
Table 1. Energy savings from audit recommendation
| Recommendation | Energy savings (kWh) | Cost Savings ($) | Emission Savings (tCO2-e) | Payback Period (Years) | Cost to Implement ($) |
| VSD on the irrigation pump | 108,580 | 19,681 | 100 | 1.7 | 33,830 |
By installing the recommendation in the audit, the business could reduce energy consumption by 24%, and costs by 22%, with carbon emission savings of 100 tCO2–e per year.
Table 2. Pre and post audit energy consumption and costs.
| Audit Metric | Pre-Audit | Post-Audit | Reduction (%) |
| Energy Consumption (kWh) | 446,114 | 337,534 | 24 |
| Cost ($) | 90,430 | 70,749 | 22 |
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 energysavers@qff.org.au.
The Energy Savers Plus Extension Program is delivered in by the Queensland Farmers Federation with support and funding from the Queensland Department of Energy and Public Works.
