Reducing Pipeline Friction Losses at a Queensland Sugarcane Farm

Overview

A Queensland sugarcane farm sought to optimise energy efficiency and reduce operational costs associated with its irrigation system. The farm operates three irrigation pumps to supply water to a range of irrigation systems, including lateral moves, travelling guns, flood irrigation, and a centre pivot. There is an existing 30kW solar system to assist in reducing energy consumption. Saturn Engineering Group conducted a Type 3 Energy Audit to evaluate the performance of the 45kW Southern Cross pump and identify opportunities for energy and cost savings.

Challenge

The farm faced high electricity costs, with the irrigation system consuming 21,484.3 kWh in the 2022/23 financial year on SAC Small Business Tariff 20. During dry seasons, electricity consumption frequently exceeded the 100 MWh threshold, resulting in the farm being transitioned to the more expensive SAC Large Business Tariff 50. Additionally, the 45kW Southern Cross pump experienced inefficiencies, with energy usage recorded at 4.00 kWh/ML/m head and water losses of 46% due to pipeline leaks. These inefficiencies limited the farm’s ability to control energy costs and maximise productivity

Proposed Solutions

  • Replacing the existing 4,700m of 150mm pipes with 200mm pipes was recommended to reduce friction losses and eliminate water leakage issues. This would decrease energy usage from 393.6 kWh/ML to 197.9 kWh/ML—a 49.7% reduction—and save 10,936.3 kWh of electricity annually.
  • Estimated capital cost: $250,000
  • Total Savings: $56,031.72 annually, including $4,224 in labour cost reductions and $11,021.60 in water
    savings
  • Payback Period: 4.5 years with a 22.4% return on investment.
  • While the current Southern Cross pump was found to operate efficiently at 72.5%, a redesign of the irrigation system by a Certified Irrigation Designer (CID) was recommended. This redesign would include optimised pump selection and operational adjustments to further reduce energy consumption.
  • A review of adding an additional 10kW solar system determined that low self-consumption rates (7– 16%) made this option currently impractical. Additional solar investment was recommended only after implementing the pipeline upgrades to maximise energy savings.
  • Maintaining electricity consumption below 100 MWh per year was identified as critical to remaining eligible for the SAC Small Business Customer Tariffs. Understanding the tariff selection process is critical. The pump station was misappropriately placed on SAC Large Business Tariff 50 last time consumption was over 100MWh annually. If this transition would occur again there would be a significant financial impact. Cost would increase from $39,195 on Tariff 44 to $94,979 on Tariff 50A.

Results

Implementing the proposed pipeline upgrade and operational changes would deliver:

Conclusion

The audit demonstrated that addressing pipeline inefficiencies and optimising irrigation practices would significantly reduce energy costs and improve system performance. While the current pump is performing efficiently, redesigning the irrigation system offers further potential for long-term energy and water savings

Key Takeaway

By upgrading infrastructure and employing targeted energy management practices, farms can achieve substantial cost and energy savings while improving operational efficiency. Saturn Engineering Group remains committed to supporting agricultural businesses in implementing sustainable and effective energy solutions.