Reaching the dry patches in Solid Set Irrigation
A Mount Mee dairy has implemented an irrigation energy management opportunity from the energy audit report they received through the Energy Savers Plus Program Extension. Through the program the business received a dairy shed energy audit, carried out by AgVet Energy, as well as an irrigation energy audit, completed by The Energy Guys, both engaged by QDO.
Replacing the pump, changing the pump location to shorten the mainline and changing sprinklers in the solid set irrigation system has increased the pumping, water, and labour efficiency.
eastAUSmilk Project Officer, Jade Chan, and I visited the site and conducted a performance test on the irrigation to evaluate the actual energy savings and outcomes achieved since implementing a recommendation from the energy audit.
The previous irrigation system did not perform well, and uniformity of the irrigation was very poor, with 20% of the area receiving nil or minimal irrigation applications. Now the dry area has been reduced to just 2% with the wetted diameter almost doubling from 7.2 to 14m.
The catch can data shows the distribution uniformity has significantly improved from under 14% to over 62%. Similarly, the coefficient of uniformity has also been improved from 43.5% to now over 78%.
The main saving for the business has been the increase in irrigatable area and improved uniformity of water application. Across the 4.4Ha an increased in pasture production of around 18 tonnes of dry matter annually could be expected.
The new system almost halved the pumping time; however, uses 541kWh more energy increasing the business’ electricity bill approximately $122 annually. The new pump has a higher energy draw 20kW per hour. With the system flow rate of 17L per second it runs for 220 hours to deliver 13.5mL, a total of 4,409kW per annum. The old pump’s energy draw was 9.6kW per hour with a flow rate of 9.3L per second it pumped for 403 hours to achieve the same 13.5mL, a total of 3,868kW per annum.
The total expenditure for the business to implement the upgrades was just over $30,000. Valuing the increased pasture production at $7,500 and minus the $122 increase in electricity bill the calculated payback period of this investment is 4.1 years with a return on investment of 24%.
There will also be a significant labour saving for the business that was not considered in the calculations. The increased flow rate allows for two lines of sprinklers to be run where previously only one line was operated at a time which will close to halve the labour required to irrigate the area.
Torie Harrison – eastAUSmilk Project Officer