Here we present results highlighting the differences that soiling and cleaning have on concentrated photovoltaic arrays (CPV) specifically focusing on ultra high concentration, >1000 Suns, photovoltaic (UHCPV) arrays in a desert environment. Soiling losses in UHCPV arrays differ from those of conventional photovoltaic (PV) arrays, to illustrate this difference we present a direct comparison between a UHCPV array and a conventional PV array showing that soiling has an approximately five times larger effect on the UHCPV array compared to a PV array. The soiling effect has been measured by taking current voltage curves of the arrays and monitoring the power output of a system's photovoltaic inverter before and after cleaning. The results indicate that in a desert environment there will be some extreme weather events that require cleaning of all types of PV modules. They also indicate that even if it is not economically feasible to clean a PV system, that a CPV system is different enough in its response to soiling and cleaning that further studies and modeling are warranted. We also discuss our current cleaning process, dust prevention methods, and cleaning schedules in an attempt to stimulate further study in these areas. (C) 2014 Elsevier Ltd. All rights reserved.