State-of-the-art egg producer finds new energy savings opportunity in sheds

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The Glenwarrie Partnership near Tamworth recently invested in a state-of-the-art caged egg laying system with packing machines and highly efficient automated feed and watering systems. However, a significant cost savings opportunity was missed: the T8 fluorescent lighting used in the sheds are around one third more expensive to run than new lighting technologies such as T5s or LEDs.

We selected dimmable T8 tubes for our lighting but our main focus was on the layer and sorting systems when we went ahead with the new shed two years ago,” says co-owner Bede Burke.

Chickens, Energy, Eggs, Energy Savings
Pilot site: “Glenwarrie” - Tamworth, NSW

Recognised for innovation

Narelle and Bede Burke run Glenwarrie Partnership, a 1400-hectare mixed-farming operation close to Tamworth, New South Wales. Their business has netted the pair industry recognition and accolades including the 2011 Tamworth Business Chamber’s Best Regional Business Award and a finalist position for 2009 Farmer of Year.

The Burkes' success stems in part from their innovative and sustainable approach to farming, achieved without compromising profitability. To date, they have incorporated several sustainability strategies on-farm, including:

installing a state-of-the-art cage production system;
growing winter and summer crops; storing grain and selling it when they have the opportunity, or using it as feed; and
incorporating an integrated feed milling system and pullet replacement enterprise into the business.

The Burkes are also heavily involved in industry and community groups.

With the operation’s capacity to repurpose waste to grow grain and to mill that grain for feed, Glenwarrie is near best-practice in closed-loop egg production. Chook waste nurtures the soil that supports crops that in turn provide feed for the layers, which produce the waste as well as the eggs. The eggs are sold directly to the local community as well as to major Australian retailers.

We use 100 percent of our chook waste and combine the waste with a mixture of soil types and trash from our crops to nurture our pasture and our crops. We might even consider generating our own power from this waste,” says Bede Burke. “The numbers need to stack up because the fertiliser is currently doing a great job.

Glenwarrie’s energy profile

Glenwarrie, Energy
Table 1: Glenwarrie energy source breakdown

The farm’s largest energy expenses are related to the daily operation of the chicken sheds as well as the farm vehicles used in cropping operations around the property.

How is energy used?

A level one audit of the farm was conducted to identify major energy usages and areas for potential savings. As shown in Figure 1, diesel for farm vehicles comprises close to 70 percent of the operation's energy usage,  with the poultry sheds using 30 percent of the energy (electricity and LPG). 

Figure 1: Glenwarrie energy end use breakup

Cost reduction opportunities

Review of the facility and energy invoices identified a list of 10 opportunities for cost reductions on farm, of which three were prioritised for further investigation by the Burkes:

  • Quick win:  Lighting upgrade;
  • Strategic: Mill conversion; and
  • Strategic: Gasification of waste to service whole farm.

The lighting upgrade from T8s to T5s will inform the design of lighting systems for the new sheds and is currently being considered as a way to help expand the business. Should additional sheds be built, the extra waste may support the business case for gasification (waste to energy for heating and other uses).

As the Burkes' poultry sheds currently operate up to 16 hours per day, seven days a week for almost every week of the year, their combined energy load supports a healthy business case for change.

There are plenty of options for upgrades at the farm; these range from a T5 conversion kit through to LED strips, equivalent to T8 tubes. Some of the existing lights are fitted with dimmable ballasts, and cost-effective LEDs now come in dimmable formats.

LED technology has matured in recent years and is enjoying widespread uptake in offices and retail outlets. The Burkes are checking on the availability of installers/suppliers in the Tamworth region. Ideally, they want to use their current sparky as the installer. The T5 or LEDs they plan to install on farm will deliver savings of $6,000 a year and upwards, to or around 25 percent of the current energy costs of lighting the Burkes' farm sheds, with an anticipated four-year payback period. LEDs will provide greater energy savings but typically are more expensive; however, they are specified to last around 10 years based on average usage patterns.

Figure 2: LED light “tube” can be retrofitted into existing fluorescent fittings

Mill conversion

The Burkes are considering a change from their current hammer mill to a disc mill but are not fully clear of the energy-use implications. The change is driven by Bede’s desire to improve the operation's grinder technology and increase on-farm automation. Other advantages of moving to a disc mill include:

  • a reduction of noise;
  • reduced levels of dust;
  • having better control over the size of grain pellets;
  • permitting expansion and increased capacity; and
  • reducing their reliance on labour.

In general terms, some of the disc-mill suppliers claim energy efficiencies over the hammer mills, but few quantity potential savings. Energy savings, if they exist, will support the business case for a new mill; further investigation of this opportunity will be undertaken during 2015. Meanwhile, Scottish research into mill efficiency provides some evidence that disc mills have cost-savings potential, assuming that when making comparisons, a larger motor is being used by the hammer mill to produce a similar quality, size and volume of feed.

Table 3: Scottish research of comparative energy use of hammer and disc mills in piggeries shows that disc mills may offer energy savings over hammer mills (in this case equal to approximatelly £ 1,095 per year)
  Disc Mill Hammer Mill
Feed tonnage (tonnes) 1,825 1,825
Energy consumption per tonne (kWh/tonne) 6 11
Total energy consumed (kWh) 10,950 20,075
Cost of power (£/kWh) 0.12 0.12
Total energy cost per year (£) £ 1,314 £ 2,409


The gasification of waste is an idea that must be compared with the benefits associated with the current use of waste on farm. Right now, the Burkes use farm and household waste to improve pastures and as feed crops. Excess waste beyond that required as fertiliser, could be used to power gas engines but may need the addition of neighbours’ waste to reach the minimum waste volumes required.

Importing waste from other chook farms poses a particular challenge due to the risk of breaching biosecurity controls (enabling the spread of pathogens), so other waste streams need to be assessed for volume and calorific value.

Currently, several streams of waste are being generated at the farm in varying intervals and quantities:

  • approximately 96 tonnes of chook manure is generated every week;
  • approximately 70 tonnes of euthanised chooks are obtained on a 19-week cycle;
  • barley and wheat straw from harvesting activities is combined with wood shavings from bedding sourced from the Tamworth equine centre as well as with 'wet egg' (broken eggs from operations) and daily chook mortalities.

At the moment, these residue and waste streams are moved to a dedicated processing area, where they are composted for eventual use as crop fertiliser. The compost is rich in nutrients and provides the necessary carbon requirements for the Burkes' crops

Could biogas be the future for powering chook sheds?

Most growers agree there's no simple solution but waste needs to be managed, especially given current Council requirements, EPA regulations and rising energy prices. So where do the opportunities lie in waste management?

Some growers derive income streams from their waste in the form of fertiliser. Others 'close the loop' and return compost and wastewater rich in nutrients to pastures, while others send it off for disposal. If and when Glenwarrie expands, it will have amassed sufficient solid waste to make it worth the Burkes' consideration of an on-site biogas operation to provide fuel for heating and/or gas for injecting into a gas genset to produce electricity for the site.

A key consideration for Glenwarrie prior to upgrading is finding answers to the following questions:

Does the site have the capacity, in terms of space and operating conditions, to stockpile waste on site?
"Yes, Glenwarrie has excellent stockpile facilities including front-end loaders and other materials-handling equipment and bays," says Bede Burke.
Glenwarrie also actively monitors the temperature of piles using a grading system and undertakes tests for pathogens. This is a contentious issue in poultry and requires careful consideration eg would soluble waste be more acceptable, rather than stockpiled as a dry waste for gasification?

What level of investment is required to set up a waste treatment plant and capture the gas?
Recent investigations in the red meat industry suggest $1m is a minimum; however, European examples of small-scale generation are common. Gasification of dry waste is very scaleable but cases in Australia are limited and generally, only at a large scale (e.g. some of the larger-scale egg or meat processing plants).

What budget and/or existing staff are available to attend to the waste treatment required?
Glenwarrie already manages waste and has allocated time, resources and equipment for this purpose; therefore additional resources are required to manage waste created on-site. Unfortunately any budget would be limited for the gasification process. For others, handling waste management and materials can often be a (not-so) hidden cost.

A further consideration is that directing waste towards gasification would mean eventually having to purchase additional quantities of fertiliser.

What to do with the excess waste?
Ccurrently, more than 4,000 tonnes of waste is generated per year, all of which is used for fertiliser on Glenwarrie's fields. Depending on the choice of waste-to-energy process (say, anaerobic digestion, or gasification), there is usually some solid waste that requires disposal. Fortunately, there's no reason this couldn't be used on the fields as fertiliser, but it would require supplementation as it would be less rich than the nutrients provided from the current composted waste.

Is the set-up scaleable with expansion?
Is it feasible to source an additional, reliable amount of waste (biomass) from surrounding properties so as to achieve greater economies of scale? Imported chicken waste has higher biosecurity issues, which need to be managed.

Glenwarrie has excellent waste-handling facilities, practices and testing protocols, making energy from waste a far more viable option. First estimates, however, suggest that the Burkes' business case doesn’t stack up.

Figure 3:Bede Burke (right) discussing waste management at Glenwarrie. Note the mounds of waste enhanced by various soils that are quarried on the farm to form highly valuable fertiliser

If the business case could be made more compelling, the next step would be to set up a gasifier to produce the gas to fuel a generator in order to service the energy needs of the farm. See below.

Figure 4: A typical industrial scale gasifier, gas fired engine and generator that can power a whole farm. Masssive energy cost savings but big capital upfront as well as ongoing maintenance

Following analysis and discussion, practical energy-efficiency and cost-saving opportunities were identified and prioritised as shown below.  


Optimising pullet-shed temperature control by covering most of the shed with Insuldeck insulation.

Insulation is a key consideration, for animal health and optimum growth rates as well as to make cost savings. At Glenwarrie, Bede had begun to improve the insulation on all sheds. One day he observed the chicks in the nursery congregating at the spot in the shed where the insulation had been improved, prompting him to accelerate the rollout of his planned insulation upgrade.

“I understood the benefits of insulation but when I saw the birds crowded under the insulated half of the shed one hot day, I immediately knew we needed to accelerate our upgrade, to protect the birds as well as reduce our heating and cooling costs," Bede recalls.

The cost of insulating the poultry building that is yet to be upgraded - the larger shed - is estimated to be around $50,000. Bede expects that this improvement will result in several benefits that will help outweigh the costs, directly and indirectly; they include:

  • better structure (improving the longevity and resilience of the facility);
  • savings in feed, estimated at 5-10 percent;
  • benefits in growth rates, estimated at 5%;
  • savings in gas for heating, expected to be around 5%; and
  • savings in energy of around 5% due to a lessened need to use cooling fans.

For more information on insulation, see the information paper ‘Insulating farm buildings’.

Figure 5: InsulDeck product information

Solar sets up a lifetime of cost savings

The business case for new sheds should compare operating costs with and without solar over the expected life of the shed.

Glenwarrie has some of the essentials to support a strong business case for solar PV, including a vast roof space with more than 3000m2 per shed, a sizeable daily peak load that varies from 20kW in winter up to 60-70kW through summer, and good alignment during daylight hours. Glenwarrie has the opportunity to install a solar PV system to offset its energy use during daytime operation (through lighting, motors and fans), with an initial estimate of ~40kW with minimal exports.

The result is $16,000 in savings.

Figure 6: Solar could provide as much as 15- 20% of the electricity load for this fam. Batteries could make a grid connection redundant, especially if the biogas-fired generator becomes a reality in the longer term enabling the Burkes to manage any supply risks.

The practice of 'no till' reduces cost as well as increasing yield and represents another energy-productivity opportunity.

The Burkes made significant savings in diesel usage by adopting a 100 percent ‘no till’ policy, using a four-season staged introduction. The following results were obtained:

Table 4: Fuel savings achieved through reduced tillage practices.

Although other factors influence use, decreased tillage has been the major contributor to this reduction in diesel costs.

Further information would be required to expand on the ancillary benefits of lower tillage. Aspects such as chemical costs for weed control, capital required to purchase new equipment, labour costs, tractor maintenance costs and other business drivers, such as soil moisture retention and yield, will be investigated in the context of increasing energy productivity on Glenwarrie farm.


When Glenwarrie implements the new lighting system, solar PV and the electricity discount via NSW Farmers' group purchasing arrangements, at least $25,000 to $30,000 will be added to the Burkes' discretionary spending power. They will save around 10 percent on their energy costs year on year.

Figure 7: Expected energy savings from continuing implementation of projects.

Enhancing business plans with improvements in energy productivity

Bede was able to identify two business opportunities that can incorporate improving the way he uses energy in order to increase farm output.

  1. Expansion by doubling the number of birds and sheds An additional pullet rearing shed is on the drawing board for Glenwarrie. If energy savings measures from the old sheds can be applied to the new sheds, the Burkes will improve their profit margin for their new venture rather than just increasing revenue.
  2. Increase local sales as a percentage of total sales This will depend on marketing their eggs as a niche product to compete with the local retailers. Promotion of their closed loop egg production system including the possibility of waste to energy technologies will strengthen the argument for a premium price on their product.

Planning for a long term future in family farming
The Burkes will continue to explore energy generation and energy efficiency options that secure the future of a family farm with an award winning history.

Over the short term, in addition to optimising his tractor set up and operating practices, Bede has applied for the 18% electricity discount and will see a lower charge from his next electricity bill. He will also be moving forward and installing insulation on the remaining large pullet shed still requiring the full fit-out.

In the medium term, Bede will convert his mill from a disc to hammer operation, knowing that while this will result in an increase in electricity use, it will also support an investment in solar PV especially if leasing arrangements can be put in place to achieve a cash flow positive result each month. The lighting system will be upgraded probably via a replacement policy that demands T5 replace the T8s at end of life rather than a one off mass replacement program.

Long term opportunities include the use of biomass to generate sufficient syngas to meet 80 percent or more of the electricity load of the farm. This opportunity is unlikely to stack up financially especially if the solar option is taken up. However other business opportunities via expanded waste management may affect these decisions in the long term.

For help identifying ways to reduce your energy costs, contact the Energy Team at NSW Farmers.




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