The farm, near Stanthorpe, produces tomatoes and capsicums and is irrigated year-round depending on rainfall. Water is supplied from an on-site irrigation dam and is replenished from rainfall and the nearby creek. It has been severely affected by the recent drought. The site is undulating and has different sized blocks and so has complex irrigation needs.
It is a small site consuming approximately 23,000 kWh per year at a cost of $7,800. The current production is approximately 1,250 tonnes per year.
The infrastructure contributing to the energy consumption onsite consists of:
- Three 15kW centrifugal pumps.
- A shed with lighting and electrical equipment.
A recent energy audit showed how improving the current systems can lead to energy and cost savings. The recommendations explored in the audit included:
- Installation of 3 x 15kW Variable Speed Drives to compensate for paddock top, including a soil moisture monitoring system to manage more efficiently the limited water at the site.
- Replacing irrigation suction pipes moving from 75mm to 150mm PVC to reduce friction losses.
- Installation of a 10kW solar system at one of the pumps.
- Tariff Change- moving from obsolete T65 to T20 Time of Use (TOU).
Table 1. Energy and cost savings from audit recommendations
| Recommendations |
Annual Energy Savings (kWh) |
Annual Costs Savings ($) |
Emission Savings (tCO2-e) |
Capital Cost ($) |
Payback Period (Years) |
| 3x15kW VSDs and soil moisture monitoring |
4,600 |
1,300 |
3.7 |
38,400 |
29 |
| Pipe replacement |
1,300 |
370 |
1.1 |
5,000 |
13.5 |
| 10kW Solar System |
4,200 |
2,200 |
3.4 |
15,000 |
7 |
| Total |
10,100 |
3,870 |
8.2 |
58,400 |
16.5 |
The grower has proceeded with the installation of the VSDs, soil moisture monitoring system and upgrading of the pipework, while solar will be considered in the future. Actual savings will be updated once the measurement and verification process is complete.
By installing the recommendations in the audit, the business is expected to reduce energy consumption by 25% and costs by 21%, with carbon emission savings of 4.8 tCO2-e per year.
Table 2. Pre and post audit energy consumption, costs, and energy productivity savings
| Metric |
Pre-Audit |
Post-Audit |
Reduction (%) |
| Energy Consumption (kWh) |
23,000 |
17,100 |
25 |
| Cost ($) |
7,800 |
6,130 |
21 |
| Energy Productivity (kWh/tonne) |
18.4 |
13.8 |
25 |
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.
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 by the Queensland Farmers Federation with support and funding from the Queensland Department of Energy and Public Works.
