diff --git a/ROSCO_toolbox/sim.py b/ROSCO_toolbox/sim.py
index 7ea930cd..39ab71f6 100644
--- a/ROSCO_toolbox/sim.py
+++ b/ROSCO_toolbox/sim.py
@@ -304,6 +304,7 @@ def sim_ws_wd_series(self, t_array, ws_array, wd_array,
 
             # Calculate the power
             gen_power[i] = gen_speed[i] * gen_torque[i]
+            gen_power[i] = gen_speed[i] * gen_torque[i] * self.turbine.GenEff / 100
 
             # Update the nacelle position
             nac_yaw[i] = nac_yaw[i-1] + nac_yawrate[i]*rad2deg*dt