An energy audit at a Southern Downs piggery investigated electricity and gas consumption and has identified opportunities to significantly reduce costs.
The site farrows and weans pigs before transporting them to a larger site for finishing. The site has several sheds for different stages of rearing, two houses, a small office and two pumps.
The farm could save electricity onsite from recommendations in the audit being:
With potential energy savings of 26,280kWh and a payback of less than a year the quickest way to improve efficiency onsite would be from the installation of new LED lighting.
| Recommendation | Energy Saving (kWh) | Cost Saving Tariff 62 ($) | Cost Saving Tariff 20 ($) | Payback Period Tariff 62 (Years) | Payback Period Tariff 20 (Years) |
| Upgrade lighting to new LEDs | 26,280 | 10,990 | 8,300 | 0.5 | 0.9 |
| Fan Upgrades | 14,400 | 4,200 | 3,700 | 9.5 | 10.8 |
| Reflective roof coating | 7,500 | 3,000 | 1,800 | >20 | >20 |
| Total | 48,180 | 18,190 | 13,800 | N/A | N/A |
Under current tariff 62 the cost savings of $10,990 per annum from the replacement of the lights could be utilised to install an adequate solar PV system. The audit considered a number of opportunities with relatively quick paybacks from the implementation of solar, including:
| Recommendation | Energy Savings (kWh) | Cost Savings Tariff 62 ($) | Cost Savings Tariff 20 ($) | Payback Tariff 62 (Years) | Payback Period Tarif 20 (Years) |
| Two Residential Solar Systems | 7,930 | 3,700 | 2,300 | 2.4 | 3.8 |
| Bore Pump: Solar only (Tariff 33) | 10,900 | 1,600 | N/A | 4 | N/A |
| Bore Pump: Solar and batteries (Tariff 33) | 13,000 | 1,900 | N/A | 11 | N/A |
| 30kW Solar System | 43,000 | 14,500 | 9,000 | 2.9 | 4.3 |
| 99.5kW Solar System | 62,000 | 19,600 | 11,400 | 4.9 | 9.4 |
Assuming the bore pump is on load control tariff 33 an initial solar system is recommended to cover the load with this showing a four-year payback. Should battery pricing decrease, then the secondary option may be worth considering. It would be worthwhile to factor this in when designing a system using a battery capable invertor.
Solar systems greater than 30kW are subject to a more complex network connection process, so the installation of the 30kW system would prove beneficial at this stage. With a capital cost of $41,000 the audit recommended remaining on tariff 62 as the system shows a payback of 2.9 years. Moving to tariff 20 the payback for the 30kW system would increase to 4.3 years. The farm will be required to move to Tariff 20 on 1 July 2021 when the Obsolete Tariffs cease.
| Location | Current Usage (kWh) | Current Cost ($) | Recommendation | Energy Saving (kWh) | Cost Savings ($) | Capital Cost ($) |
| Piggery | 115,272 | 36,607 | Lighting and 30kW Solar PV |
26,280 43,000 |
5,500 14,500 |
5,000 13,000 |
| Main Bore Pump | 10,385 | 2,001 | Solar PV only | 10,900 | 1,600 | 10,000 |
| Farmhouse | 15,435 | 5,408 | Solar PV | 7,900 | 3,700 | 8,100 |
| Total | 141,091 | 44,016 | N/A | 88,080
(62%) |
25,300
(57%) |
36,100 |
Implementation of the recommendations at the piggery will ensure that the farm is able to remain a small electricity user and able to remain on small business tariffs, with 62% of electricity savings over total consumption, 57% reduction of associated cost and emission savings of 76 tCO2-e per year.
Implementation of the above recommendations from the energy audit would significantly reduce the kWh and dollar costs per unit of output at the farm with new KPIs reduced.
| Benchmark | WEANED PIGS | ANNUAL ENERGY Total (kWh) | Annual Energy Cost ($) | KPI (kWh/Weaned Pig) | KPI ($Cost/Weaned Pig) |
| Pre-Audit | 21,510 | 141,091 | 44,016 | 6.55 | 2.04 |
| Post Audit (Gas Saving) | 21,510 | 53,011 | 18,716 | 2.46 | .87 |
From the table the farm could realise a 42 per cent of reduction in energy costs per unit of output.
The audit identified a number of cost-effective initiatives on site that could reduce gas consumption by 1,083GJ per annum with emission savings of 49 tCO2-e, including the items in the table below:
| Recommendation | Energy Saving (GJ) | Cost Savings ($) | Payback (Years) | Capital Cost ($) |
| Solar Hot Water (Farrowing Shed) | 590 | 24,500 | 3.1 | 3,000 |
| Temperature Control for Heat Mats | 415 | 18,500 | 0.4 | 7,000 |
| Insulation on Hot Water pipes | 78 | 3,500 | 0.8 | 1,600 |
| Total | 1,083 | 46,500 | 1.4 | 11,600 |
| Installation of Biogas | 1,680 | 67,000 | 5.3 | 400,000 |
The audit considered the opportunity to the install a biogas facility capturing and recycling gas produced from the piggery. This would reduce the high costs attributed to LPG, though due to production numbers, biogas production is limited and is not recommended unless the piggery expands into the future.
At a cost of $400,000 and a potential payback of 5.3 years the biogas is a more long-term consideration depending on the future direction of the farm.
Implementation of the recommendations in the table above would significantly reduce LPG gas consumption and dollar costs per unit of output with new KPIs seen.
| Recommendation | WEANED PIGS (ANNUAL) | ANNUAL GAS USE (GJ) | KPI (MJ/PIG) |
| Pre-Audit | 21,510 | 2,102 | 0.097 |
| Post Audit (General Recommendations) | 21,510 | 1,019 | 0.047 |
| Post Audit (Biogas) | 21,510 | 422 | 0.019 |
The table shows the farm could achieve a 52 per cent reduction in gas consumption as a result of implementing the general recommendations. Should the farm capture and use biogas than a further 28 per cent reduction in LPG may be seen.
With LPG costs considerably larger than electricity, the farm should consider low cost, recommendations to allow additional capital expenditure to implement some of the larger energy saving measures.
The figures show there are significant electricity savings to be realised onsite leading to reduced KPIS.
An energy audit is a good investment
An energy audit is a great way for a business to cut costs and boost productivity. Find out about what’s involved in an energy audit 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.
