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Gum Creek

Case study: Backyard ingenuity reduces energy costs in Griffith

[Click here to download a PDF version of this case study]

Gum Creek

Biomass is a fuel source that could replace diesel for farmers prepared to make the investment but the technology is not readily accessible. At Gum Creek the use of biomass is under investigation and with over $200,000 in pumping costs the incentive to innovate is strong for third generation farmer Ian Blight. Ian typifies the Ag Innovator dedicating time, machinery and effort into developing prototype equipment that will collect and compress biomass into a form that can be readily incinerated to produce gas. He has also modified a 280hp diesel to save over 10 percent in diesel costs. NSW Farmers is supporting this investigation.


Ian runs Gum Creek, an 11,000 acre farm in the Riverina area. The farm grows rice and grazes cattle, and utilises irrigation technologies (flood) to aid crop production. Ian is a passionate tinkerer, and has explored a number of options around his existing equipment, including substituting conventional diesel with used-vegetable oil, and re-wiring and replacing pump fans on diesel engines with evaporative cooling pads, salvaged from old air conditioning units. Walking around the property, it is common to see equipment that predates Ian and his time running the farm. Old machinery is reused, or fixed up, and components are used to supplement the current operation.There are many ways to reduce energy use on farm, or take advantage of new technological advancements to enhance farming practices. Ian Blight is looking to do all of these things, as well as investigating the use of existing crop waste to provide energy for his own property, and his neighbours.

Gum Creeks energy profile

Table 1: Gum Creeks Energy breakdown
Table 1: Gum Creeks Energy breakdown

The farm’s largest energy expense is pumping water around the property.

Table 2: Gum Creek's Energy Breakdown by End-Use Purpose
Table 2: Gum Creek's Energy Breakdown by End-Use Purpose

Figure 1: Gum Creek Energy Use by Type and Purpose – with 70 percent of the energy used for pumping water around the property it’s easily the greatest focus for savings.

Cost reduction opportunities

The team from NSW Farmers and Energetics worked with Ian to better understand his operation and the way that energy is used on the property. This consultation resulted in the identification of opportunities that, if implemented, would reduce costs and enable more efficient farm operations.

Biomass energy

Ian has a particular interest in trying to becoming self-sufficient for energy needs. He is a tinkerer and innovator who has been piloting his own straw compactor to create feedstock for use in a gasification unit to create his own syngas for fuelling various engines around the property.

In keeping with the theme of re-use, Ian’s main interest lies in determining a way to use his existing crop residues for other tasks. In this case, Ian is working on developing a machine to collect and compress ‘trash’ or crop waste to produce gas to fuel his diesel engines especially those used for pumping water. The operation requires the trash to be compressed to a suitable density, and then fed through a ‘gasifier’ which will unlock the energy from within the bricks to form the gas. Given time and development, the biomass and subsequent gas has the potential to offset a substantial amount of the current diesel pumping cost.

Straw, or trash as it is sometimes called, is currently left behind and generally considered a waste product and burnt. Based on some initial research done by Ian, he believes he should have more than enough residual straw to produce gas to fully offset his diesel pumping requirements. It comes down to how cost effective it is to collect and prepare the straw and then how much time is needed to achieve this outcome.

Ian is thinking about first building a system that could be placed in close proximity to one of his bores, and be able to dual fire the engines on a mixture of diesel and his own gas.  Once the system is proven, either the diesel engines could be converted to run on higher volumes of gas or he might need to acquire new gas engines to run fully on his own gas. He hopes to commence testing in early 2015.

This system could be expanded out onto multiple bore pumps. When thinking long term, Ian is also wondering how he might be able to generate his own electricity to supply his and neighbouring properties using a gas-fired generator. As Ian puts it “this is not just an interest, this is about improving the finances of the farm. The cost of pumping has crept up significantly and this has encouraged us to look at efficiencies.”

Optimising existing diesel engines for pumping

After tinkering with the main bore pump for the property, a 280hp Cummins, Ian has managed to save about 10 percent of this engine’s diesel use i.e. around 8,000 litres of diesel a year. He has achieved this by

  1. Disconnecting the cooling fan (~10hp) and instead have cooling provided by a jacketed sleeve around the bore water pipe being passed through HX to cool the engine coolant. Once passed straight through the HX, the warmed water gets discharged with the main bore water.
  2. Fitting a heat exchanger to cool the intake air to below 60°C and increase turbo boost pressure (after turbo before heads).
  3. Using an old evaporative cooler on the air intake with water being taken off the bore line. This cools inlet air down to improve thermal combustion on particularly hot days.
  4. Fitting a fuel heat exchanger to cool the fuel before it goes into engine.
  5. Having operated this pump on used vegetable oil in times past, but Ian is no longer able to purchase the oil at a cost effective rate to justify the hassle.

The combined savings is estimated to be 10 percent or more of diesel costs per year for the Cummins. The next savings opportunity is to apply these modifications to the Hino pump motor which pumps a similar amount of water as the Cummins and so Ian can expect to double his savings to be similar to the Cummins. So total savings will be significant at around 16,000 litres.

Tractor set up tyres and ballast set up

Farmers are often concerned about achieving maximum life for tyres without considering the potential fuel savings that may be gained by adjusting tyre pressure to suit application.

When towing equipment, tractors often need additional ballast on front and back of the tractors in order to achieve optimal stability and in particular to achieve the optimum level of traction referred to as ‘wheel slip’. This indicator typically between 4-8 percent, provides a target for farmers to set up their ballast and tyre pressures to suit the country they are working and the job or application being performed. Excessive wheel slip can mean tyre pressures are too high or ballast is underweight while too little wheel slip can be due to underinflated tyres (excess wear, fuel use and puncture potential) or underweight ballast. These dynamics are influenced by the country, soil type and moisture as well as the application (sowing, spraying, and tillage) and the implement used. Visit NSW Farmer’s factsheet on tractor set up for more information: ‘Tyre Pressure and Fuel Efficiency’.

Ian has advised that his focus on tyre pressure and ballast has dropped over the last couple of years and so expects his savings to be mid-range especially if he adjusts ballasting weights on their John Deere 8320 and John Deere 8110.

Other energy savings opportunities

Other savings opportunities include taking advantage of electricity discounts offered through the utility, looking at ways of optimising the operation of the existing solar pumping units, ensuring that panels are orientated correctly, and looking at new insulation  for the homestead, to ensure that the house is kept warm in the winter and cool in the summer.

To summarise, the NSW Farmers Energy Team found a number of energy efficiency and cost saving opportunities. The priorities decided by Ian after considering the effort and impact on his business plans are  as follows

Table 3: Full list of opportunities with priority opportunities highlighted.
Table 3: Full list of opportunities with priority opportunities highlighted. 

Figure 2: Gum Creek generates a large amount of waste in the form of straw that can be used as biomass to generate enough gas to run the bore pumps that deliver water to approximately 900ha of paddocks for both winter and summer crops. NSW Farmers are helping Ian with determining the feasibility of this innovative use of crop waste

Figure 3: Optimise panel configuration of existing solar bore pump – greater output over shorter period of time. Adding an additional panel at a modest cost of a few hundred dollars can sometimes deliver the electricity of less panels on a tracker costing $10,000 or more
Figure 3: Optimise panel configuration of existing solar bore pump – greater output over shorter period of time. Adding an additional panel at a modest cost of a few hundred dollars can sometimes deliver the electricity of less panels on a tracker costing

Outcomes

Optimising the 2 main bore pumps, tractor set up and the existing solar system will save Gum Creek around $16,000 a year or 6-7 percent of their energy costs.

The next time Ian needs to pump water to prepare for sowing he will save approximately $15,000 in diesel costs from minor modifications to his engines

Figure 4: Expected energy savings from continuing implementation of projects - the yellow column represents potential gas from biomass generated on the farm. The savings are achieved by converting diesel pumps to gas fired off setting diesel costs by an assumed 65 percent (allowing for occassional shortage of biomass.
Figure 4: Expected energy savings from continuing implementation of projects - the yellow column represents potential gas from biomass generated on the farm. The savings are achieved by converting diesel pumps to gas fired off setting diesel costs by an a

Savings from biomass could approach $145,000 per year.

Planning for a long term future in family farming

With the assistance of NSW Farmers’ Energy Innovation Program, Ian will continue to explore energy generation and energy efficiency options that secure the future of a family farm with a long history.

Over the short term, in addition to optimising his existing Solar PV system, Ian will focus on tractor set up and tyre pressures to optimise wheel slip.

In the medium term, Ian will modify his Hino powered pump to achieve the 10 percent savings achieved by his Cummins powered pump.

Long term opportunities include the use of biomass to generate sufficient syngas to meet 80 percent of pumping costs or (approximately 66 percent of total energy costs) . This investigation will include the ongoing development of the compactor for crop waste and discussions with neighbours on the collaborative effort required to ensure adequate supply of waste to meet their energy needs or at least a substantial proportion.

Beyond biomass Ian and NSW Farmers’ innovation team will monitor the development of electric tractors, especially for lighter duties such as chaser bins and spraying.

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