Berrybank Farm Energy Recovery project, Windermere, Victoria
Since then, the owners have built allied potting mix and fertiliser businesses around the enterprise. They now plan to create even further efficiencies, with a project underway to use the heat generated from these processes to reduce the piggery's heating and cooling costs.
Berrybank Farm is located at Windermere, between Ballarat and Learmonth in south-west Victoria and is owned by the family company, Charles I. F. E. (Integrated Farming Enterprise) Pty. Ltd.
Berrybank Farm originally established their piggery in 1970. Twenty one years later, they invested two million dollars and undertook an ambitious project to collect methane from the piggery waste to generate electricity for the farm and feed any excess into the electricity grid.
Berrybank Farm primary and secondary digesters together with the shed containing the generator in the fore-ground
By 2011, pig numbers had expanded to 20,000 and along with generation of power, the business has expanded to produce potting mix and fertiliser from piggery waste whilst saving over 100 megalitres of water annually.
Seven-step process to generate electricity and heat
The key stages in the process of turning piggery waste to energy involves:
- automatic and continuous waste collection
- grit removal
- slurry thickening
- primary anaerobic digestion
- secondary anaerobic digestion
- biogas purification
- generation of electricity.
Electricity is generated by combusting methane gas in a generator, referred to as a 'genset'. The gas is purified to remove hydrogen sulfide which would otherwise corrode the engine.
Whilst there is a ready use for the electricity, IFE General Manager, Jock Charles, sees use of the heat as the next step in efficiency to be addressed.
Three-stage heat recovery plan
Heat is a bi-product of biogas production that is often undervalued in Australia. With rising electricity costs, finding ways to use this heat can create efficiencies for business and benefits for the environment. This three stage heat recovery plan (not yet installed) involves:
Stage 1: Fitting gensets with exhaust heat exchangers and a temperature control system, thereby using this otherwise wasted energy to heat the boilers that maintain the temperature in the biodigester.
Stage 2: Retrofitting thermal heat pads to 260 existing, and 140 renovated farrowing pens to ensure piglet survival during cold months. This stage will replace a total of 492 heat lamps (175 watt each).
Stage 3: Using an absorption chiller to convert excess heat in summer months to cooling for 400 farrowing pens. This will use a fan and four 30 kW heating and cooling coils. This could also deliver cool air into the grain silos to keep the temperature below 17°C and therefore inhibit weevil infestation.
Integrating with other businesses
Potting mix and fertiliser
Berrybank Farm's Total Waste Management System also incorporates the manufacture of potting mix and organic fertiliser from digestates (organic bi-products) of the anaerobic digestion process. The fertiliser is used on the farm's 1000 hectares of crops, while the potting mix is sold through garden centres and nurseries in Victoria, New South Wales and Tasmania.
Jock Charles in front of his bioenergy facility with his potting mix product
To maintain consistent fertiliser and potting mix products, the pigs are fed a high quality diet from the farms own feed stocks which consists of an 800 tonne grain storage facility and 70 tonne hay storage facility. Two hundred tonnes of feed is prepared on site per week. Any purchased feed must meet strict quality parameters.
A robotic pellet stacker packing potting mix for shipping
Organic fertiliser being loaded into the spreader be- fore being applied to crops
Improving efficiencies further
Equipment for energy recovery project
The equipment required for such a project is extensive. Apart from a range of pumps, sensors, heat regulation devices and plumbing equipment, the major items needed are exhaust heat exchangers, absorption chiller and heating and cooling coils.
In order to use the heat in the piggery, a new flooring system and textile diffusers will also be required. The total investment cost for the 3-stage project is $720,000, with each of the three stages providing a return on investment of at least 17%.
Pigs produce effluent which provides Berrybank Farm's energy source
Caterpillar biogas generator or Berrybank Farm's 'genset'
Benefits of the additional energy recovery project
- Based on electricity costs as at July 2011, including the value of Renewable Energy Certificates available for sale, Berrybank's energy recovery project will save the business an estimated $82,500.
- Based on current generator running times, the 3- stage heat recovery process will recover at least 1,200 kWh of energy per day (438 MWh per year). This means that the generators can run longer,
producing more electricity, expected to be around 190 MWh per annum.
- Fifty per cent of this power saving will be used to provide additional heat to the boilers.
- Most energy produced from the biogas system is used on site, however, surplus electricity is sold into the grid.
- Approximately 740 tonnes of CO2 is saved per annum.
- Further economic benefits are also expected due to improved piglet growth rates as a result of enhanced climate control within sheds, lower heat related deaths in summer and further reductions in electricity use through using surplus energy in summer to cool stored grain.
For further information view the bioenergy section.