We report on the results obtained from field performance monitoring of four different roof mounted PV systems in Abu Dhabi, UAE, for a period of one year. The PV systems consisted of multi-crystalline silicon (m-Si) and single-crystalline silicon (c-Si) solar cell technologies. The monthly average and annual performance parameters of the PV systems assessed include the total energy generated, final yield (Y-F), energy payback time (EPBT), capacity factor (CF) and CO2 emission reduction. The comparison showed that systems with m-Si modules have higher monthly total average final yield than systems with c-Si modules. Moreover, a comparison with PV systems operated in different locations around the world also indicated that our PV systems had much higher final yield and capacity factor of 6.2 kWh/kWp/day, and 21%, respectively. The results and comparisons are discussed. (C) 2015 Elsevier B.V. All rights reserved.