Low cost energy opportunities deliver over $20k of energy savings for mixed cropping farm in Northern NSW

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Quote from Ken Stump

Ken and Judy Stump are the owners of Windella, a mixed cropping/grazing farm operation located between Walgett and Moree. The farm grows a mix of cereal crops, chickpeas and cotton. Most of the property is dedicated to dryland cropping, but around 15 per cent of the nearly 10,000ha supports irrigated cotton. The Stumps also have a herd of beef cattle which graze on the land and fluctuate between 100-500 head. They have a few full time farm hands, including a manager who lives on site. The Stumps also employ seasonal workers to assist with farming operations.

Windella’s energy use

The Windella farming operation requires around 450,000 litres p.a. of diesel fuel for sowing, harvesting, trucking/transport and pumping. The farm owns five tractors, and operates four pumps (three diesel and one electric). Water for irrigation and on-farm use is taken either from a nearby river or pumped out of a bore, depending on availability. Bore water is about five times more expensive than river water, which is a major factor when deciding which of the pumps to use.

The property has three homesteads (the main house, farm manager’s house and housing for additional workers) and uses electricity for general lighting, heating/cooling, and other activities in the farm sheds.

Blackouts, brownouts and energy availability

Living on a floodplain, at the fringe of the electricity networks in Eastern Australia, power reliability is a major concern at Windella. The property is well over an hour’s drive from the nearest large town, and during floods many of the roads in the area become treacherous and impassable. Interruption in power supply can be a major inconvenience for the farm’s daily operations.

Fuel Type Consumption (p.a.) Units Conversion to GJ factor GJ Cost Cost /Unit Cost /GJ
Table 1: Windella energy breakdown
Diesel 450,000 litres 0.0386 17,370 504,000 $1.12 $29.02
Electricity 231,208 kWh 0.0036 832 59,728 $0.26 $71.76
Petrol 6,000 litres 0.0342 202 9,000 $1.50 $43.86
Total /Averages       18,408 $572,728 $0.96 $48.21

The farm’s largest energy expense is split between running tractors, pumps to lift and distribute ground water, and the operation of other farm vehicles for transporting grain. While Windella is a dryland cotton operation, where tractors rather than pumping dominate diesel use, finding savings in pumping can still provide significant cost reductions.

Fuel Type Purpose Energy Used (GJ)
Table 2: Windella energy inventory
Diesel Various 4,854
Diesel Tractors 4,130
Diesel Pumping 3,358
Diesel Other vehicles (utes) 3,098
Diesel Harvester & Excavator 1,930
Electricity Pumping 432
Electricity Homestead & other 400
Petrol Plane 205
Total   18,408
Energy use at Windella
Figure 1: Windella energy use by type and purpose
NSW Farmers


Cost reduction opportunities

At Windella the NSW Farmers' Energy Innovation Team found the following energy efficiency and cost saving opportunities.

Opportunity Cost Savings (p.a.) Payback
Table 3: Full list of opportunities.
Solar/diesel hybrid for workshop & cottages or grid connected system for Windella Under investigation (possibly $9000 for initial grid-connected system at Windella)

Under investigation

($1,500, 6,000 kWh for first grid connected system option)
Under investigation (possibly 6 years for small grid connected system)
Voltage optimisation $10,000 Up to 5 percent 4-5 years

Energy efficiency induction checklist and operator training on:

  • adaptive driving
  • fuel monitoring
  • Correct ballasting
  •  Tyre pressures
No capital $11,000/ 10,000 litres of diesel Immediate
Pumping (electric): Load shifting (off peak) on bore pump capacity $1,200 for switch + installation by electrician $1,500 1 yr
Domestic storage tank sufficient height to gravity feed homestead from bore Under investigation Under investigation Under investigation
Install low load Tailwater pump at Creek station $70,000 $10,000 7 yrs
Creek pump configuration – pump type, pipe bends, etc. Under investigation $5,500, 5,000litres Under investigation
Savings from group buying discount (17%) through Origin No capital $8,500 Immediate
Solar Hot Water system $8,000 $400 20 yrs
Replace halogen lamps with LEDs $1,000


3,800 kWh
<1 yr
Solar hot water system $6,000 $1,000 6 yrs
Replace halogen lamps $1,000 $800 (3,000kWh) <1 yr
Hot water system - turn setpoints down to 65°C or switch off when not in use No capital $200 <1 yr
Total/Average $97,000 $42,000 (solar will reduce this total) Average: 4 yrs (rounded)


Focus on more efficient use of tractors

The Stumps decided the priorities were in more efficient tractor set ups and adaptive driving to save fuel costs: a potential saving of 5-10% in diesel usage.

As part of the general induction process, the Stumps are emphasising the importance of recognising energy use on a daily basis with new farm workers taken through an “energy efficiency checklist”. In addition, the NSW Farmers' Energy Team is working on a matrix of correct tyre pressures and ballast weights for each of the farm’s tractors. This matrix will be used to ensure that tractors are running as efficiently as possible, and will provide guidance to vehicle operators who will also have training in adaptive driving.

Quote from Judy Stump

Load shifting and Electricity monitoring delivers quick wins

The Stumps have evaluated their existing irrigation and pumping layout and switched their electric pumping to off-peak rates (at a cost of $1,200 for a switch including installation by an electrician). They are now considering using electricity generated from solar to further cut energy costs.

In addition, the Stumps have now installed individual electricity meters on each of the cottages (which house farm hands and manager, John). Each house is now responsible to pay for their metered consumption. Ken has already noticed that this has resulted in a substantial reduction in their electricity use (by about 20%).

Solar PV for the homestead

In order to improve energy reliability, and reduce existing electricity costs on the farm, the Stumps have been investigating solar PV, including battery storage, as either a back up (for blackouts) or as a way of replacing electricity from the grid. At this point, the financial case for purchasing sufficient battery storage to go “off-grid” is still a difficult one. However the increased confidence that comes with knowing and controlling your own energy supply is making this option more and more attractive.

The Stumps are considering the installation of an 8kW solar system with batteries and a 35kVa diesel genset backup. This is currently being investigated and compared with a small grid-connected system in the range of 3-4kW (this sizing is based on the quarterly billing values from which daily usage can be inferred[1]).

This opportunity can be firmed up with additional onsite energy monitoring to determine optimal sizing and the costs involved in installing an appropriate system.

[1] Initial sizing based on a general rule of thumb of 30% of daily usage.

Did you know?

Modifications as simple as ensuring temperature settings are correct can lead to significant savings over time, with one degree Celsius of temperature adding about five percent to the energy use. More advanced control systems can provide more accurate control of temperature, lighting and fans, leading to savings throughout the system. Setpoints are subject to Food safety standards. For more information refer to some of the following resources:

More information on cool room setpoints is also available in NSW Farmers’ Case Study for Birrah.

Good insulation and or cool rooms inside a building such as at Windella can save 1-6% on their energy use if away from direct sunlight and exposed to cooler air when opened.  For more information on cool room efficiency see NSW Farmers' information paper Energy efficient cool rooms and refrigeration.

A cool room at Windella
The Stumps have a small cool room in their home at Windella.
NSW Farmers


A number of efficiency and energy cost management opportunities have already been implemented:

  • hot water tank set point has been turned down to 65 °C;
  • halogen lights throughout various cottages have been replaced with LEDs;
  • a group buying discount of 17% off their electricity has been secured from Origin Energy; and
  • a switch has been installed on their domestic bore so that it runs during off-peak hours.

Additional opportunities such as monitoring fuel use, setting KPIs, communicating with, and in some cases, training operators will require time and effort but further fuel savings can be substantial, ranging from 5- 20% (as much as $9,000 a year). Another benefit is improved fuel security, as some farms experience misappropriation of fuel for personal use.


Next season Ken and Judy can expect to save $9,000 in fuel thanks to their efforts to build a consistent approach and commitment to efficiency across their team of operators.


The Stumps upgraded their lights in their homestead from 50 watt halogen downlights to 10 watt LEDs saving up to 80 % of their lighting costs. This equates to perhaps as much as $1,000 in savings year after year! The savings are good but the message can be even more powerful, especially when chasing diesel savings of more than $9,000 a year.

Quantifying quick wins has inspired the Stumps to progress other more difficult savings initiatives and provides a symbolic story or message for others, including seasonal operators, who will be relied on for those diesel savings. The spiel at induction will now include this symbolic example of action and savings.

Beyond technology upgrades time of use provides big savings. Changing the times of operation on the bore pump to off peak electricity generates savings for Windella of around $1,000 a year.

Energy savings at Windella
Figure 4: Expected energy savings from continuing implementation of projects
NSW Farmers


Savings per year (GJ) 1000
Savings per year (%) 6
Savings per year ($) $42,000

Future productivity gains at Windella

With the assistance of the NSW Farmers’ Energy Innovation Program, Ken will continue to explore energy saving opportunities that deliver real savings and productivity outcomes for Windella.

In the short term, in addition to installing new fuel measurement equipment, diesel fuel savings will be achieved by communicating efficiency goals to operators and ensuring that tractor set up (including adjusting tyres and ballasting points) is optimal for major tasks and critical operations.

Over the medium term, solar PV will be investigated further and may begin saving the Windella farm money after 4-8 years (depending on the size of the system).

Long-term opportunities include drawing on localised solar PV to power pumps, and examining the potential to power pumps and engines using biogas or biofuel, sourced from local on-farm waste or nearby agricultural operations. Such opportunities require a higher level of investment and may not be cost effective currently.  However their development should be monitored as technologies improve and become more commercially viable.

The stumps are also evaluating options for changing to different diameter pumps and potentially implementing VSD motors (Variable Speed Drives), which would allow pumps to operate at a number of different “best efficiency points” and maximise fuel efficiency.



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