The National Centre for Engineering in Agriculture at the University of Southern Queensland, Toowoomba has released a report into “Improving Energy Efficiency on Australian Irrigated Cotton Farms” by benchmarking the direct energy consumption in Australian irrigated cotton production. The report looks at all on-farm energy consumption but in regards to pumping, raises some interesting observations.
Based on realistic pumping industry values, the average pump efficiency is about 80%, the average drive train efficiency is 95%, the average large diesel motor efficiency is about 35% and the average electrical motor efficiency is about 90%.
Using these average values we can calculate that one ML of water lifted one metre of height using diesel driven pump systems will use about 0.96 litres of diesel at a cost of $0.96. For an identical pumping system with an electrical motor, we can calculate that one ML of water lifted 1 metre of height would use 4.0 kiloWatt-hours (kW.h) of electricity at the cost of $1.
It is important to note that despite the very different efficiencies between diesel and electric motors, when translated to some work undertaken, the difference in diesel and electricity costs is not significant based on diesel fuel cost of $1 per litre (after rebate) and average electricity prices of $0.25 per kiloWatt-hour (kW.h).
Based on these figures, the expected payback period on conversion to a large scale solar pumping system would be in the area of 4-5 years depending on a range of site conditions including government rebates, size of storage, irrigation cycles and actual diesel and electrical costs.
If you want to discuss a solar pumping solution for large scale irrigation , please contact Kevin Hopkins on 0430 500 184 or email firstname.lastname@example.org.
The full report can be downloaded here.