In this paper, a techno-economic study of the impact of mirror slope errors is achieved. The geometric and optical efficiencies of a parabolic trough collector, installed at Green Energy Park research facility, are studied. Following, yields analysis of a 1MW, power plant is conducted and modeled under semi-arid climate. The plant is simulated by considering the geometric and optical proprieties of the studied parabolic trough collector and using high-quality meteorological data measured at ground level for one year. Finally, an economic investigation is presented, taking the Levelized Cost of Electricity as an indicator. According to the results, the global average mirror slope errors measured by the robust deflectometry technique are 4.59 mrad. The calculated experimental optical efficiency is then 65.4%. Consequently, the optical efficiency drop of the studied collector due to theses slope errors is 12.44%. Based on the simulation results of the modeled power plant, the monthly average electrical losses due to the impact of mirror slope errors can reach 20.53 MWh(e). The results of the economic evaluation showed that 12.44% of optical efficiency increased the LCOE by 14.14%. Therefore, the quality specifications and assessment of collectors before and during solar field assembly are important. (C) 2020 Elsevier Ltd. All rights reserved.