Energy Savers
Central Queensland

Central Queensland Irrigators

Proposed
60
Proposed Energy Savings
Industry
Irrigators
Location
Central Queensland
Pumps
Bore
Solution
Solar PV, Pumps

Farm Profile

The energy audit assessed three separate irrigation systems, consisting of line shaft bore pumps supplying water to three centre pivots and a lateral move. The auditor assessed the pumps and determined that they are delivering less water than expected and has made staged recommendations to identify the causes and rectify with payback periods ranging between 4 and 17 years.

This case study will focus 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, the farm could reduce its consumption of grid electricity by over 60%, reducing energy costs by around 50%.

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.

Solution Pump 1 Pump 2 Pump 3
Annual Hours 3,900 1,900 4,300
Current kWh/ML/m 8.81 5.44 6.83
Solar PV System Size 20kW 20kW 30kW
Estimated Cost to Implement (after STCs) $22,000 $22,000 $33,000
Annual Power Savings (kWh) 23,000 14,000 33,000
Annual % Power Savings 41% 41% 41%
Annual Cost Savings $6,000 $3,700 $6,700
Payback (years) 3.7 6.0 5.0
Carbon Emissions Reduction (t CO2-e) 18.6 11.1 27.1

 

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.

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 28,000kWh).

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.