A 400–acre mixed enterprise consisting of a piggery producing sweet corn, green beans and broccoli could benefit from a recent energy savers audit. The piggery has 2.2 cycles per year finishing on average 2600 pigs per annum. This case study is part one looking at the basic energy efficiency measures in respect to the piggery, while part two HERE focuses on irrigation improvements and the large standalone battery system.
Energy Savers
Farm Profile
The total energy consumption onsite is distributed through two meters. One is considered a Large Asset Customer (LAC), while the other a Small Asset Customer (SAC). The first meter recorded 302,135 kWh with maximum demand of 100 KVA in demand at a cost of $54,523 per annum. The second used 15,117 kWh with $4,664 in costs. The total energy consumption is 317,252 kWh, costing $59,187 per annum. Irrigation of two cropping paddocks is associated with the two meters, one on the larger account, and the other smaller account.
Initial inspection of voltage at the board showed some major load imbalance. This could be attributed to operating single phase pumps and fans at each distribution board around the farm. This imbalance should be investigated further as it is not ideal for 3 phase operations. It can contribute to heating in boards, switchgear, cable joints and nuisance tripping at the circuit breaker.
With that in mind this case study focused on the following efficiency measures relating to the piggery sheds, with a total capital investment of $68,395:
- Power factor correction (PFC)
- LED lighting upgrade
- Installation of a 27kW Solar PV
- Roof treatment and Fans
Table 1. Audit recommendations showing energy and cost savings
| Recommendation | Cost to Implement ($) | Energy Savings (kWh) | Cost Savings ($) | Payback Period (Years) | Carbon Savings (tCO2-e) |
| Power Factor Correction | 8,000 | Demand saving 4kW | 1,673 | 4.7 | N/A |
| LED lighting upgrade | 495 | 560 | 92 | 5.4 | 0.5 |
| Solar PV 27kW | 45,900 | 48,415 | 9,213 | 5 | 44.5 |
| Roof Treatment (reflective paint) and Fan | 14,000 | 18,825 | 3,082 | 4.8 | 17.3 |
| Total | 68,395 | 67,800 | 14,060 | Average 4.9 | 62.3 |
The audit showed power factor varied from 0.87 to 0.94. Power factor is the measure on how well the site uses the power being delivered, with 1.00 being ideal. With the old motors and aged plant, the power factor will be lower. A new PFC unit could save the site $1,673 from a reduction in demand.
The older light fittings should be replaced with new LEDs. The auditor also suggested painting the existing tin roof of the shed with a heat- reflective paint to reduce the heat in the building and therefore the ventilation energy consumption. Finally, a three phase 27kW roof mounted solar PV system should be installed which would reduce consumption by roughly 48,415kWh per annum.
A happy pig results in improved health and weight gain. Energy is required to maintain a comfortable environment for the pigs with the use of heat mats, fans, misting and evaporative systems to control the climate, ease distress and increase production weight. An energy metric linked to production can then be applied to the production output, in this case kWh/pig has been used.
By installing all the recommendations in the audit, energy consumption could be reduced by 22%, costs by up to 24% and carbon emissions by 62.3 t CO2-e per annum.
| Metric | Pre-Audit | Post-Audit | Percent Reduction (%) |
|
Energy Consumption (kWh) |
317,252 | 249,452 |
22 |
| Costs ($) |
59,187 |
42,127 |
24 |
| kWh/pig |
116.2 |
90.1 |
22 |
An energy audit is a good investment
An energy audit is good investment and will give you the baselines required and ways to improve using the latest in efficient technology and best management practices. An energy audit is a great way for a business to cut costs and boost productivity.
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.
