A horticulture farm located near Stanthorpe could benefit by saving energy, time and money from recommendations in a recent energy audit. The audit recommended installing a Variable Speed Drive on the cold room unit and a 12kW solar system to offset the farm energy consumption by 15%, with emission savings of around 27.1 tCO2-e per year.
Energy Savers
Summary
The farm, near Stanthorpe, produces tomatoes and salad greens using hydroponics and protected cropping systems. Water is supplied from several on-site irrigation dams which are replenished from rainfall and bores.
It is a large site consuming approximately 230,000kWh per year at a cost of $60,000 across the 3 NMIs that were assessed. The farm is expanding the hydroponic and protected cropping areas to make better use of the limited water available. The farm has already invested in a 6kW solar system to help offset electricity costs.
The infrastructure contributing to the energy consumption onsite consists of:
- A main 15kW centrifugal pump
- A smaller 5kW hydroponic circulating pump
- 2 large Cold rooms
- Large packing shed
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:
- Tariff analysis, which found potential savings of $2,500 per year by changing the Time of Use tariff 62 at the main packing shed by the flat-rate tariff 20S.
- Install a Variable Speed Drive on the cold room unit to better manage the different load requirements of crops and improve the life span of the compressor.
- Installation of a 12kW solar system at the main packing shed, which already has a 6kW system.
- Replace the main pump to improve the efficiency of the irrigation system.
Table 1. Energy and cost savings from audit recommendations
| Recommendations | Annual Energy Savings (kWh) | Annual Cost Savings ($) | Emission Savings (tCO2-e) | Capital Cost ($) | Payback Period (years) |
| Tariff Change | – | 2,500 | – | – | – |
| VSD on cold room | 11,000 | 3,700 | 9 | 17,000 | 4.5 |
| 12kW solar system | 10,000 | 2,700 | 7.8 | 20,000 | 7.3 |
| Pump replacement | 13,000 | 2,300 | 10.3 | 11,000 | 4.8 |
| Total | 34,000 | 11,200 | 27.1 | 48,000 | 5.5 |
The grower reviewed the audit report and will consider the recommended upgrades in their future business planning.
By installing the recommendations in the audit, the business could reduce energy consumption by 15% and costs by 19%, with carbon emission savings of 27.1 tCO2-e per year.
Table 2. Pre and post audit energy and cost savings
| Metric | Pre-Audit | Post-Audit | Reduction (%) |
| Energy Consumption (kWh) | 230,000 | 196,000 | 15 |
| Cost ($) | 60,000 | 48,800 | 19 |
A real-time energy meter has recently been installed, which will allow the business to understand their energy consumption, being able to find further demand reductions onsite. Read more about HERE.
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 by the Queensland Farmers Federation with support and funding from the Queensland Department of Energy and Public Works.
