Solar irrigation systems have become an affordable climate-friendly technology for large farms and small-scale farmers in developing countries. But we need to fully manage and supervise solar irrigation systems to avoid the risk of water being unsustainable.
Further declines in solar PV panel prices may drive reforms in sub-Saharan Africa. Only 3% of the cultivated land in the area has an irrigation system that is seven times lower than the global average.
The opportunities created by solar price cuts further force us to ensure that appropriate water management and governance systems are put in place.
In assessing the current economic viability of solar irrigation systems, we need to consider a variety of factors. This includes the size and configuration of the irrigation system, the storage capacity and convenience of the water resources, the depth of the irrigation wells, the remoteness of the irrigated areas, and the type of soil to be irrigated. The "return period" for such investments depends on the above factors, crops and markets, and whether there are government price subsidies.
Solar irrigation pumps can also lead to unsustainable groundwater extraction, as farmers may seek to expand their acreage or switch to crops that require more water. For example, about 30% of aquifers in India have been considered critical.
Although drip irrigation systems designed to meet local conditions can save water, it is unrealistic to have it automatically achieve water conservation at the farm level. Before making various irrigation policy decisions, we should first make appropriate accounting for water resources within a larger territory. Because rainfall, surface water, groundwater, soil moisture, and evaporation processes that correspond to different land use patterns are part of the same water cycle system.
Solar panels can also generate energy without irrigation, providing a great opportunity to run rice shellers, mills, water purifiers and refrigeration equipment, which will contribute to rural development and income generation. Under certain conditions, solar energy can also become a "economically profitable crop" if farmers can choose to reduce over-exploitation of water by storing excess energy and selling it to the grid.