diff --git a/powersimdata/scenario/scenario_info.py b/powersimdata/scenario/scenario_info.py
index 180adccbf..6fa87474e 100644
--- a/powersimdata/scenario/scenario_info.py
+++ b/powersimdata/scenario/scenario_info.py
@@ -1,3 +1,5 @@
+import warnings
+
 from prereise.gather.constants import abv2state, state2loadzone, \
     interconnect2loadzone
 
@@ -36,10 +38,10 @@ def area_to_loadzone(self, area):
         elif area in {'Texas', 'Western', 'Eastern'}:
             loadzone_set = interconnect2loadzone[area]
         elif area == 'all':
-            loadzone_set = list(self.grid.zone2id.keys())
+            loadzone_set = set(self.grid.zone2id.keys())
         else:
             print("%s is incorrect." % area)
-            raise Exception('Invalid area')
+            raise ValueError('Invalid area')
         return loadzone_set
 
     def check_time_range(self, start_time, end_time):
@@ -58,12 +60,12 @@ def check_time_range(self, start_time, end_time):
                 (end_time not in self.pg.index):
             print('Available time range [%s, %s]' % (str(self.pg.index[0]),
                                                      str(self.pg.index[-1])))
-            raise Exception('Invalid time range')
+            raise ValueError('Time range out of scope!')
         start_i = self.pg.index.get_loc(start_time)
         end_i = self.pg.index.get_loc(end_time)
         if start_i > end_i:
-            print('start_time falls behind end_time!')
-            raise Exception('Invalid time range')
+            raise ValueError('Invalid time range: '
+                             'start_time falls behind end_time!')
         return start_i, end_i
 
     def get_capacity(self, gentype, area):
@@ -81,7 +83,7 @@ def get_capacity(self, gentype, area):
             (self.grid.plant['type'] == gentype) &
             (self.grid.plant['zone_name'].isin(loadzone_set))]['Pmax'].sum()
         if total_capacity == 0:
-            print('Warning: no such type of generator in the area specified!')
+            warnings.warn('No such type of generator in the area specified!')
         return float(total_capacity)
 
     def get_generation(self, gentype, area, start_time, end_time):
@@ -129,7 +131,7 @@ def get_profile_resource(self, gentype, area, start_time, end_time):
                               (self.grid.plant['zone_name'].
                                isin(loadzone_set))].index)
         if gentype not in self.profile:
-            raise Exception('Invalid resource type')
+            raise ValueError('Invalid resource type')
         query_profile_df = self.profile[gentype][plant_id_list]
         self.check_time_range(start_time, end_time)
         total_resource = query_profile_df.loc[start_time:end_time].sum().sum()
@@ -176,7 +178,8 @@ def get_capacity_factor(self, gentype, area, start_time, end_time):
         total_hours = end_i - start_i + 1
         total_capacity = self.get_capacity(gentype, area)
         if total_capacity == 0:
-            raise ZeroDivisionError('Division by zero')
+            raise ZeroDivisionError('No such type of generator in the area '
+                                    'specified. Division by zero.')
         total_generation = self.get_generation(gentype, area,
                                                start_time, end_time)
         cf = round(total_generation / (total_hours * total_capacity), 4)