On the face of it, solar photovoltaic (PV) equipment seems a perfect match for irrigation pumping. And it can be. But a recent project in northern Victoria showed some interesting results on the best size of solar to suit their needs.

Firstly, for those of you using diesel, then solar will be cheaper. While it’s not just as simple as adding a solar array to your existing setup, it has been done successfully and is well worth exploring – but that’s probably a subject for another day.

The project involved a customer with a mix of sub-surface drip irrigation and gravity flood irrigation. Their irrigation operating season was October – April. In practice, this meant quite intense watering patterns, requiring regular pump operation during the summer months and then zero consumption through the rest of the year.

Viewed as an aggregate, the load was a good candidate for solar. However, since there were several properties, each with up to 100kW of pump load and individual meters. When we drilled down to the electricity use at site level, it was apparent that sites were highly intermittent, and not at all correlated in time. Modelling the output of a PV system at that location, and matching it against individual site pump consumption showed clearly that there would be significant periods of time when solar and pump usage did, and did not coincide.

Solar array at Kerang

By running hourly models of the PV output and consumption, we were able to determine that

1. The relationship between financial return and size of the PV system was fairly constant, regardless of PV size.
2. There were significant opportunities to move consumption into cheaper offpeak electricity tariff times

The investigation underlined again the advantages of using advanced system modelling to accurately predict results. It also highlighted how energy, while important, is just one aspect of good agricultural management.

Based on this analysis, we are exploring how to incorporate energy considerations into the decision support system. Watch this space!