Variable-speed drives in photovoltaic pumping systems for irrigation in Brazil

Thanks to recent technological advances and the falling price of photovoltaic modules, photovoltaic pumping systems (PVPSs) are more competitive for use in irrigation, especially in remote areas where other power sources are unreliable or unavailable. Nevertheless, several issues remain regarding the purchase, maintenance and replacement of PVPS components. One alternative for traditional PVPS configurations is the use of a variable-speed drive (VSD). The performance of this type of configuration was tested both at a pumping test facility and in the field at a variety of sites. The application of a variable-speed drive can enable the use of locally-manufactured pumps which are not necessarily designed specifically for photovoltaic applications, thus facilitating their replacement and maintenance. Furthermore, VSDs also enable the operation of pumps in power ranges higher than most commercial photovoltaic pumps. VSDs can thus potentially further improve the economic competitiveness of a PVPS, as shown by Life Cycle Cost analysis comparing a conventional (PVPS-C) and a variable-speed drive pumping system (PVPS-VSD). This paper examines these as well as other technical and economic aspects of the application of variable-speed drives for irrigation in Brazil.