Despite the high upfront cost, the market for SPISes is growing fast globally, with large-scale government investment in SPISes subsidy projects to be found in countries such as India and China, where thousands of small-scale farmers without access to the power grid can now irrigate sufficiently without the need for expensive diesel-run solutions.
In South Africa, farmers need, on average, about 80 m3/ha of water, pumped for about 9 h/d. This means that the farmers can expect to spend about R108 000/ha upfront on an SPIS, Reinders explains, adding that the advantage, however, is that the operating costs are almost zero.
Therefore, it often makes more sense – in the short term – for farmers to simply draw power from the grid, despite the operating cost being higher.
“The biggest drawback in Africa is infrastructure. In many places, electricity from the grid is simply not available. Farmers stuck without access to grid power often revert to using diesel power, which is about five times more expensive than grid power per kWh,” Reinders tells Engineering News.
Diesel-powered irrigation systems cost a lot less upfront than an SPIS, but these systems are also less environment-friendly and more expensive to run than the solar-powered ones. For small-scale farmers, investment in diesel-powered systems could have a negative impact on the farmer’s bottom-line over time, owing to the higher operating costs.