The cost of pumping bulk water using mains electricity or diesel has become a significant burden on agricultural productivity, with most irrigation farmers having to cover six-figure energy bills.
While electricity is more efficient for pumping than diesel, high network charges and connection costs in rural areas have inhibited growth in the electrification of irrigation pumping. Therefore, irrigators across all farming systems are increasingly looking to solar power for solutions.
Technically, there is no limit to the volume of water that can be pumped using solar power, as a solar array can be sized to meet any scale of power demand. The business case for solar-powered irrigation on a given farm depends on factors, including the number of months of pumping per year, the time of day when irrigation occurs, and the potential to export and sell unused energy. A solar PV system that provides the required energy for an irrigated farming enterprise can entail significant investment and detailed site-specific analysis.
Irrigation water requirements vary markedly, depending on the crop to be watered. Orchards, for example, typically require year-round irrigation, with increased water requirements during fruit production. Solar pumping solutions are naturally well suited to such horticultural irrigation systems, significantly if the crops are grown to need more water during summer, such as blueberries and fruit trees.
Irrigation for broadacre crops usually occurs during specific periods of the year. Some broadacre crops, such as rice and lucerne, require irrigating over six to eight months of the year, whereas the irrigation period for crops such as wheat and mung beans is shorter.
When pumping is seasonal or irregular, it is essential to identify how your solar power will be used when it is not needed for irrigation. If you do not have other uses for electricity on the farm or the ability to export and sell unused power, consider installing a smaller system that is integrated with different power supplies.
Solar can supplement mains power, reducing bills in high tariff periods. A great strength of solar is its ability to be integrated with electricity from other sources. This means that installing an extensive enough system to meet your peak seasonal irrigation load is not strictly necessary. Alternatively, a free-standing system (not grid connected) could be sized to meet year-round base load, with diesel generation used to top up total power in peak load periods. Many possible configurations and site-specific analyses are essential to identify the optimal design and size for your property and farming system.