diff --git a/py_wake/utils/area_overlapping_factor.py b/py_wake/utils/area_overlapping_factor.py
index 3efcd645a3ddde549abe18907fff9a9fe986c906..05941392dadf773ace7b09998b1206da3aa307ed 100644
--- a/py_wake/utils/area_overlapping_factor.py
+++ b/py_wake/utils/area_overlapping_factor.py
@@ -43,7 +43,7 @@ class AreaOverlappingFactor():
 
         The calculation formula can be found in Eq. (A1) of :
         [Ref] Feng J, Shen WZ, Solving the wind farm layout optimization
-        problem using Random search algorithm, Reneable Energy 78 (2015)
+        problem using Random search algorithm, Renewable Energy 78 (2015)
         182-192
         Note that however there are typos in Equation (A1), '2' before alpha
         and beta should be 1.
diff --git a/py_wake/wind_turbines.py b/py_wake/wind_turbines.py
index 86f619054995a6718d459b6cd67b56bb44d7c455..203fce873320b8e3632f9ee4777ad3fe902c9ac0 100644
--- a/py_wake/wind_turbines.py
+++ b/py_wake/wind_turbines.py
@@ -129,7 +129,7 @@ class WindTurbines():
             P = np.array([self.power_funcs[t](ws) for t, ws in zip(type_i, ws_i)])
             return CT, P
         else:
-            return self.ct_funcs[t[0]](ws_i), self.power_funcs[t[0]](ws_i)
+            return self.ct_funcs[int(t[0])](ws_i), self.power_funcs[int(t[0])](ws_i)
 
     def set_gradient_funcs(self, power_grad_funcs, ct_grad_funcs):
         def add_grad(f_lst, df_lst):