Where’s the Problem? Electric Motor or the Pump

Overview

A diverse farming operation in regional Queensland engaged an energy audit to address inefficiencies across its irrigation and grain storage systems. The audit analysed three main energy-consuming assets: a bore pump, a river harvest pump, and grain silo shed motors. This case study outlines the findings, proposed solutions, and potential benefits for reducing energy consumption and costs while improving operational sustainability.

Challenge

The farm relied on legacy equipment, including a 30-year-old bore pump and river pump with an oversized outdated electric motor, both exhibiting suboptimal efficiency levels in either the pump or electric motor. Additionally, the grain silo shed’s motorised operations contributed to high electricity consumption. Combined, these systems consumed over 138,000 kWh annually, costing more than $47,000. With two of the three systems on transitional tariffs nearing expiration, the enterprise needed a comprehensive strategy to mitigate escalating energy costs and improve efficiency.

Audit Findings

Name Efficiency Annual Consumption Assessment
Bore Pump
The bore pump operated at just 44.7%, consuming 7.62 kWh per megalitre per metre of lift.
34,060 kWh costing $11,681 under Tariff 62.
The existing pump was identified as inefficient, leading to excessive energy use and higher costs.
River Harvest Pump
The pump achieved better performance at 89.7%, with an energy use of 4.17 kWh per megalitre per metre of lift.
75,972 kWh costing $26,335.
The motor driving the pump, though functional, lacked the energy efficiency of modern alternatives.
Grain Silo Shed Motors
Fifteen motors of varying sizes supported grain transfer, aeration, and loading activities.
29,493 kWh costing $9,072 under Tariff 20.
A solar array was identified as a suitable solution for offsetting electricity usage and reducing costs.

Proposed Solutions

  • Replace the existing pump with a Franklin FPS-78/5 submersible pump to achieve a 46.9% increase in water flow rate and reduce electricity consumption by 10,612 kWh (42.6%).
  • Capital Cost: $31,330.
  • Projected Annual Savings: $3,375 with a payback period of 9.3 years under Tariff 66.
  • Install a high-efficiency 200 kW TECO 3-phase motor to reduce energy consumption by 6,248 kWh (16.6%).
  • Capital Cost: $15,500.
  • Projected Annual Savings: $2,168 with a payback period of 7.1 years under Tariff 66.
  • Solar Array Installation (Grain Silo Sheds)
  • Install a 7kW solar array to offset 5,775 kWh (19.6%) of electricity consumption and export surplus energy to the grid.
  • Capital Cost: $7,840.
  • Projected Annual Savings: $1,957 with a payback period of 4 years under Tariff 20.

Key Benefits

Implementation Plan

The proposed solutions align with the farm’s operational needs and sustainability goals. The bore and river pump upgrades focus on immediate efficiency improvements, while the solar array installation capitalises on renewable energy to offset electricity demand. A measurement and verification plan will track energy savings post-implementation to ensure targets are met.

Outcomes

By adopting these measures, the farm can expect a significant reduction in energy use and costs while enhancing operational resilience. The investment of $54,670 in energy upgrades positions the business as a leader in sustainable farming practices, with benefits extending beyond cost savings to improved environmental outcomes.

Conclusion

This case study demonstrates how targeted energy efficiency initiatives can deliver meaningful improvements for agricultural enterprises. By upgrading outdated equipment and integrating renewable energy solutions, the farm achieved a balance between operational needs and sustainability. The project serves as a practical example for other farms seeking to modernise their energy systems and future-proof their operations.