Energy Savers
Wide Bay Burnett

Queensland Sugar Cane & Sweet Potato Farm

Proposed
60
Energy Savings
43.8
Savings
86,323
Industry
Cane
Irrigation
Travelling Gun and Drip
Pumps
Centrifugal
Technology
Change Irrigation type, Variable Speed Control, Tariffs
Capital Cost
$260,000

Summary

A recent energy audit showed how improving the current systems can lead to energy and cost savings. The recommendations explored in the audit included the installation of VFD at pump one and two, replace the travelling gun irrigation system with a lateral move, and conversion to Tariff 33 at all pumps.

A sugarcane and sweet potato farming enterprise located in Moore Park Beach could benefit from a recent Energy Savers Audit. Farming requires constant decision making to maximise production and profit. Crops are often rotated due to season changes, weather variations and higher value products though sometimes the systems in place are outdated.

The total area of cropping lands consists of 64.4 ha and is serviced by two pumps. The current irrigation system is run by two individual irrigation pumping units. Pump site one (Bottom pump) supplies water to 20.8 ha of sweet potato crops through trickle irrigation. It has a high input flow rate and is capable of sustaining systems like a low pressure lateral move. This system currently uses mechanical valves to manage the fluctuation in supply pressure and to reduce pump output. Pump site two (Top pump) supplied water to 23.2 ha of sugarcane through a big gun travelling irrigator. It also has a high input flow rate and is capable of the simultaneous operation of up to three travelling gun irrigators. It too was installed prior to the development of variable frequency technology and uses mechanical valves. Both pumps receive their water supply from the Bundaberg Irrigation Water Supply system which is managed by Sunwater.

Energy consumption from the two pumps sites showed that a total of 91,453 kWh at a cost of $24,226 was used during the 2018-2019 period. A recent energy audit showed how improving the current systems can lead to energy and cost savings. The recommendations explored in the audit included:

  • Install two Variable Frequency Drives (VFD) to existing irrigation systems.
  • Complete electrical works to move to Tariff 33.
  • Replace existing irrigation systems with lateral move irrigators (50% share).

Table 1. Energy savings from audit recommendations

Recommendations Annual Energy Savings (kWh) Annual Cost Savings ($) Emission Savings (tCO2-e)  Capital Cost ($) Payback Period (years)
Install VFD in two pumps 35,940 10,404 28.8 19,000 1.9
Change to Tariff 33 6,261 5,000 0.8
Change irrigation system 18,747 69,658 15 236,000 5.4
Total 54,687 86,323 43.8 260,000 2.7

 

One recommendation from the Energy Audit was to install a lateral move irrigator on both systems. Results show a cost reduction due to a reduction in the operating head and increased pumping flow rate. This system could also result in an increase in production capacity of up to 20% per hectare in sugarcane.

It is also estimated that the adoption of tariff 33 will result in a 26.4% reduction in business as usual energy costs. The combined effect of the recommendations will reduce the annual energy demand by around 54,687 kWh saving $20,073. It will also increase sugarcane production by an estimated 350 tonnes of cane annually. While estimated additional annual sweet potato production of 100 t/sp valued at $10/18kg carton net of harvesting is an increase of $2,750 per ha (Total $55,000 per year). It is estimated that annual energy cost saving will be $20,073 and the potential net return from improved productivity will be $66,250.

By installing the recommendations in the audit, the business could reduce energy consumption for pumping by 60% and costs by 356%, including productivity gains, with carbon emission savings of 43.8 tCO2-e per year, which will enhance the profitability and productivity of the farm.

Table 2. Pre and post audit energy consumption, costs, and energy productivity savings

Metric  Pre-audit  Post-audit  Reduction (%) 
Energy Consumption (kWh)  91,453 36,766 60
Cost ($)  24,266 -62,097 356
Energy Productivity (kWh/ha) 1,420 571 60


An energy audit is a good investment
 

An energy audit is a great first step in moving a business towards a more efficient future by reducing energy use, costs and carbon emissions onsite.  

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. 

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