A recent energy audit showed how improving the current systems can lead to energy and cost savings. The recommendations explored in the audit included installing Variable Speed Drives in two pumps as well as a 30kW solar system at the 45kW pump, with a total capital cost of $89,500, energy savings estimated as 26% of total consumption and emission reductions of 24.9 tCO2-e per year.
Energy Savers
Summary
The farm, in the Lockyer Valley, produces a variety of vegetables and is irrigated year-round depending on rainfall. Water is supplied from on-site irrigation dams which are replenished from rainfall. Another property has access to bores and an irrigation scheme.
It is a large site consuming approximately 120,000 kWh over the three NMI’s assessed at a cost of $29,000.
The infrastructure contributing to the energy consumption onsite consists of:
- An 18.5kW irrigation pump on a property in a different location which supplies a centre pivot
- A large 55kW irrigation pump
- A 45kW transfer pump
A recent energy audit showed how improving the current systems can lead to energy and cost savings. The energy audit recommended the following changes to improve efficiency and reduce costs:
- Installing a Variable Speed Drive on the 18.5kW pump to allow better control of the pump while irrigating using different pressurised systems.
- Installing a Variable Speed Drive on the 55kW pump to allow better control of the pump while irrigating using different pressurised systems.
- Installing a 30kW solar system on the 45kW pump. Changing the transfer schedule to match the solar output would allow for higher utilisation of the energy generated.
Table 1. Energy and cost savings from audit recommendations
| Recommendations | Annual Energy Savings (kWh) | Annual Cost Savings ($) | Emission Savings (tCO2-e) | Capital Cost ($) | Payback Period (years) |
| VSD on the 18.5 kW pump | 8,345 | 1,890 | 6.8 | 5,500 | 2.9 |
| VSD on the 55 kW pump | 7,000 | 1,650 | 5.7 | 30,000 | 18.2 |
| Solar system on the 45 kW pump | 15,375 | 6,100 | 12.4 | 54,000 | 8.8 |
| Total | 30,720 | 9,640 | 24.9 | 89,500 | 10 |
Following the audit report recommendations, the grower will review the recommendations and may proceed in the future.
By installing the recommendations in the audit, the business could reduce energy consumption by 26% and costs by 34%, with carbon emission savings of 24.9 tCO2-e per year.
Table 2. Pre and post audit energy and costs savings
| Metric | Pre-Audit | Post-Audit | Reduction (%) |
| Energy Consumption (kWh) | 120,000 | 89,280 | 26 |
| Cost ($) | 29,000 | 19,360 | 34 |
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.
