The output power of wind farms in real world applications is lower than the theoretical output which is largely due to wake effect. So as to maximize the output power, the wake effect of upstream wind turbines on downstream ones should be attenuated. Thus, arrangement of wind turbines in a wind farm is an essential issue that needs to be tackled. This study pursues the aim of finding an optimal layout. Initially, Jensen wake model is applied to simulate the wake effect. Then, genetic algorithm is employed to optimize the wind farm layout considering multiple factors that include different hub heights, rotor diameters, variable induction factors, power and capacity factor curves. Three cases including constant wind–constant direction, constant wind–variable direction and variable wind–variable direction are studied and compared with previous studies. The results indicate that the efficiency of the wind farm for case 1 is 96.71% which is a high record comparing to the previous literature. For Case 2 and 3, the annual wind farm capacity factor (CF) is found to be 97.96 and 97.51%. The power output of Case 1, 2, and 3 are 5.6855 × 108 kWh, 5.6694 × 108 kWh, and 4.5572 × 108 kWh, respectively. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019