This case study is focused on the comparison of options to reduce energy consumption from the grid by installing solar panels at the sites. If all the recommendations of the audit are implemented, including the respective pump replacement recommended, the farm could reduce its consumption of grid electricity by over 60%, reducing energy costs by around 55%.
The Audit recommended a solar system at each of the pumping sites that will offset approximately 41% of the power for each of the systems. The pumps are all used for different hours each year due to changes in annual rainfall.
|Solar PV Size
|Capital Cost (after STCs)
|Capital Cost Pump Inspection
|Power Savings Solar and Pump (kWh)
||23,000 + 21,000
||13,700 + 5,000
||33,500 + 11,200
|Cost Savings Solar and Pump ($)
||6,000 + 5,500
||3,700 + 1,000
||6,600 + 2,400
|Payback Solar/Pump (years)
||3.7 / 8.7
||6 / 36.4
||5 / 16.4
|Total Emission Reductions (t CO2-e)
The audit compared four solar system sizes for each pump: 5kW, 10kW, 20kW and 30kW and the sizes recommended represent the most effective choice for the farm. The interval data was not available at each of the sites and therefore the above analysis is based on estimates and does not correlate times that energy is consumed by the pumps or generated by the proposed solar panels.
In each of the above cases, the smaller systems had better payback periods because they would export less power as a proportion of overall generation. As the proportion of export increases, the payback period increases as the Feed-in-Tariff revenue per unit is less than the cost of the power offset.
As a final assessment, the auditor considered the option of combining all pumps onto one NMI and installing a solar PV system large enough to maintain the farm as a small user. An 80kW system was considered potentially suitable with a Payback Period of 5.9 years.
The total energy savings estimated including pumps replacement and solar systems correspond to 64% of total energy consumption, with 55% of associated cost savings and emission reductions of 86.7 tCO2-e per year.
See our Bowen Horticulture Farm Case study where the costs of two 30kW Solar PV systems were compared for different sheds with payback periods of between 3.3 and 4.5 years HERE. In this case, the system with higher utilisation (offsetting over 40,000 kWh) had a better payback period than the smaller utilisation (offsetting 18,000kWh).
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 firstname.lastname@example.org.
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.