Increasing Irrigation Efficiency Through Pump Replacement and Performance Verification

Overview

A Queensland farming enterprise commissioned an energy audit and implemented the results, a pump replacement project that enhanced irrigation and energy efficiency. Following the installation of a new creek pump, a detailed measurement and verification assessment was conducted to evaluate the performance improvements. This case study outlines the results of the assessment, highlighting significant energy, cost, and operational benefits.

Challenge

The farm relied on an ageing mixed-flow China pump to lift irrigation water from an adjacent creek into a supply channel. Despite achieving moderate efficiency levels (67.4%), the pump’s performance had begun to decline due to wear and tear. Additionally, the pump’s capacity to deliver sufficient water flow was a limiting factor, prolonging irrigation cycles and increasing operational costs. In 2018/19, the creek pump consumed 20,046.83 kWh of electricity at a cost of $4,667.68 under Tariff 66. Its energy efficiency was measured at 4.30 kWh per megalitre per metre of lift, which indicated room for improvement.

Proposed Solution

An energy audit recommended replacing the existing pump with a 400HW-7 mixed-flow China pump. The new pump was selected based on its higher efficiency, improved water flow rate, and suitability for the farm’s irrigation requirements.

Implementation

In January 2022, the farm installed the new pump along with a 480mm diameter discharge pipe to minimise friction losses caused by increased water flow. This pipe had to go under an existing road that increase the cost and complexity of the project. The total capital cost of the project was $111,700, covering the pump, associated components, and installation.

A comprehensive measurement and verification assessment was conducted in February 2022, approximately one month after the pump’s commissioning. The assessment compared the new pump’s performance against the old system and validated the expected outcomes:

  1. Efficiency Improvements
  • The pump’s efficiency improved from 67.4% to 80.4%, representing a 19.3% increase.
  • Energy usage decreased from 4.30 kWh/ML/m head to 4.00 kWh/ML/m head, a 7% improvement.

  1. Electricity Savings
  • Annual electricity consumption was reduced by 39.8%, from 20,046.83 kWh to 12,062.5 kWh.
  • Electricity cost savings totalled $2,145.79 per year under the current tariff structure.

  1. Operational Benefits
  • The water flow rate increased significantly, from 159 L/s to 348 L/s.
  • Irrigation cycles were shortened from 63 days per season to 40 days, reducing labour requirements. This resulted in annual labour savings of $11,500.
  • Total Savings: Combined electricity and labour savings amounted to $13,645.79 annually.

  • Payback Period: The project’s payback period was recalculated at 8.2 years, with a return on investment (ROI) of 12.2%.

  • Emissions Reduction: Annual greenhouse gas emissions were reduced by 6.5 tonnes of CO₂

Key Takeaways

The M&V assessment validated the predicted improvements in energy efficiency and operational performance. By replacing an outdated pump with a modern, higher-capacity model, the farm achieved:

Conclusion

This project highlights the transformative potential of targeted energy efficiency upgrades in agriculture. The combination of rigorous pre-installation analysis and post-installation verification ensured that the investment delivered measurable benefits. The farm’s success demonstrates how adopting modern irrigation technologies can drive economic and environmental improvements, setting a benchmark for other agricultural businesses to follow.