Laidley Horticulture Farm
Energy Savings: 12% | Cost Savings: $7,300 | Capital Cost: $35,800 | CO2 Savings: 22.8 | Project Status: implemented
Industry:
Horticulture
Location:
South-East
Pump Type:
Centrifugal, Submersible
Irrigation Type:
Drip, Travelling gun
Technology:
Irrigation and Pumps, Variable Speed Drives
The farm, near Laidley, is a large producer of vegetables and has a large packing shed. The farm is irrigated year-round depending on rainfall. Water is supplied from on-site irrigation dams and is replenished from bores and rainfall. The irrigation systems are gradually being changed from high-pressure systems to drip tape to be more water-efficient and as a result, there is a variety of pressures required.
It is a large site consuming approximately 234,000 kWh per year at a cost of $53,000, irrigating over 70 hectares and harvesting 4200T of vegetables per annum. The farm has already installed a 100kW solar system.
The infrastructure contributing to the energy consumption onsite consists of:
- A 30kW centrifugal pump
- An 11kW submersible pump
- A 22kW centrifugal pump
- 2 large cold rooms totaling 53kW of cooling
A recent energy audit showed how improving the current systems can lead to energy and cost savings. The energy audit recommended the following changes to improve efficiency and reduce costs:
- Replacing the 30kW pump with a new pump with a VSD, to allow for accurate adjustments of irrigation pressure and reduce electricity consumption.
- Adding a VSD to the 11kW submersible pump.
- Adding a VSD to the 22kW pump.
- Installing a 12kW ground-mounted solar system at the site of the 11kW submersible pump.
Table 1. Energy and cost savings from audit recommendations
| Recommendations | Annual Energy Savings (kWh) | Annual Cost Savings ($) | Emission Savings (tCO2-e) | Capital Cost ($) | Payback Period (years) |
| 30 kW pump replacement with VSD | 11,000 | 3,000 | 8.9 | 19,000 | 6.3 |
| VSD on 11kW pump | 12,400 | 3,300 | 10 | 8,800 | 2.7 |
| VSD on 22kW pump | 4,750 | 1,000 | 3.8 | 8,000 | 8 |
| 12kW solar system | 13,900 | 4,100 | 11.3 | 21,600 | 3.4 |
| Total | 42,050 | 11,400 | 34 | 57,400 | 5.1 |
The grower has proceeded with the installation of the new pump and the 3 VSDs, with estimated energy savings of 12% over total farm consumption, cost savings of 14%, and carbon emission reductions of 22.8 tCO2-e per year. Actual savings will be updated once the measurement and verification process is complete.
Table 2. Pre and post implementation energy consumption, costs, and energy productivity improvements.
| Metric | Pre-Implementation | Post-Implementation | Reduction (%) |
| Energy Consumption (kWh) | 234,000 | 205,850 | 12 |
| Cost ($) | 53,000 | 45,700 | 14 |
| Energy Productivity (kWh/tonne) | 56 | 49 | 12 |
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.
