A South-East piggery has saved money and reduced energy consumption after implementing the recommendations from a recent Energy Savers Audit. The solution installed is a 23kW solar PV system.
This case study is part one looking at the primary energy efficiency measures in respect to the piggery, while part two HERE focuses on irrigation improvements and the large standalone battery system.
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.
The total energy consumption onsite is distributed through two meters. One is considered a Large Asset Customer (LAC), while the other is a Small Asset Customer (SAC). The first meter recorded 302,135 kWh with a maximum demand of 100 KVA at a cost of $54,523 per annum. The second used 15,117 kWh with $4,664 in costs. The total energy consumption onsite is 317,252 kWh, costing $59,187 per annum.
Initial inspection of voltage at the board showed some major load imbalance. This could be attributed to operating single-phase pumps and fans at each distribution board around the farm. This imbalance should be investigated further as it is not ideal for 3 phase operations. It can contribute to heating in boards, switchgear, cable joints and nuisance tripping at the circuit breaker.
With that in mind, this case study focused on the following efficiency recommendation explored in the audit, relating to the piggery sheds:
Table 1. Energy and cost savings from audit recommendation
| Recommendations | Cost to Implement ($) | 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 | 39.2 |
| Roof treatment (reflective paint) and Fan | 14,000 | 18,825 | 3,082 | 4.8 | 15.2 |
| Total | 68,395 | 67,800 | 14,060 | Average 4.9 | 54.9 |
The audit showed power factor varied from 0.87 to 0.94. Power factor is the measure of 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 $1,673 from a reduction in energy demand.
A happy pig results in improved health and weight gain. Energy is required to maintain a comfortable environment for the pigs using heat mats, fans, misting and evaporative systems to control the climate, ease distress and increase production weight.
The grower has proceeded with the installation of a 23kW Solar PV system instead of the 27kW system, with savings measured in a Measurement and Verification (M&V) process, as outlined in Table 2.
Table 2. Estimated and Actual energy and cost savings.
| Metric | Audit estimation | M&V calculation | Variation (%) |
| Energy Savings (kWh) | 48,415 | 45,876 | -5 |
| Cost Savings ($) | 9,213 | 8,716 | -5 |
Since the installed system is smaller than the recommended option, the savings achieved are greater than expected – 41,245kWh of estimated savings by adjusting the original model to a 23kW system – influenced by the optimal orientation of panels and the higher sun period than modelled. Most solar generation has been used onsite, so the cost savings are also greater than expected for a 23kW system.
By installing the recommendation in the audit, the farm has reduced energy consumption and costs by 15%, with carbon emission savings of 37.2 tCO2-e per year.
Table 3. Pre and post implementation energy, costs, and energy productivity improvements.
| Metric | Pre-Audit | Post-Audit | Reduction (%) |
|
Energy Consumption (kWh) |
317,252 | 271,376 |
15 |
| Costs ($) |
59,187 |
50,471 |
15 |
| Energy Prodcutivity (kWh/pig) |
122 |
104 |
15 |
An energy audit is a good investment
An energy audit is a 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 by the Queensland Farmers Federation with support and funding from the Queensland Department of Energy and Public Works.
