A dairy in the Darling Downs region, milking 280 cows, has implemented a photovoltaic (PV) system with load shifting through chilling water management opportunity based on the energy audit report the farm received through the Energy Savers Plus Program Extension.
Through the program the business site received a dairy shed energy audit carried out by AgVet Energy and a further assessment carried out by Websters Group followed by an electrical site analysis performed by Solar Energy & Battery Storage Solutions (SEBSS) all engaged by eastAUSmilk.
The goal of the business was to reduce electricity costs by firstly lowering supply from the grid and secondly, with the reduced grid supply, transitioning from the demand tariff to a consumption tariff such as Tariff 20.
Implementing the solar system along with water chilling allows for increased solar utilisation by the business as large portions of the business' energy use occurs outside of daylight hours with milking. Excess solar energy is used during the day to chill water and then the cold water is used through a plate cooler to reduce the temperature of milk before it reaches the vat, offsetting energy use by the refrigeration system.
Monitoring the farm energy use from July to October 2021 an average PV energy utilisation of 67 per cent was achieved.
The total load was 319 kWh/day with an average 210 kWh/day being supplied by the grid. With a grid supply charge of 29.46 c/kWh and a 109 kWh being offset by PV the system conservatively achieves an annual electricity bill saving of more than $11,700.
Additionally, on average 53.92kWh were exported daily at a feed in rate of 6.581 c/kWh the PV system is generating export income of over $1200.
The total expenditure invested by the business was about $76,000. With over $12,900 in annual savings from reduced grid supply and income generated from solar PV export the calculated payback period of this investment is 5.9 years with a return on investment of 17pc.
Implementing the 30kW PV system the grid supply has been under 272 kWh/day. Four consecutive months of this reduced grid supply makes the business eligible for a consumption only Tariff such as T20. This will provide the business further annual savings reducing the payback period and increasing the returning on investment.
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