diff --git a/hub/city_model_structure/energy_systems/energy_system.py b/hub/city_model_structure/energy_systems/energy_system.py
index fdac1513..a5324047 100644
--- a/hub/city_model_structure/energy_systems/energy_system.py
+++ b/hub/city_model_structure/energy_systems/energy_system.py
@@ -60,9 +60,9 @@ class EnergySystem:
     self._demand_types = value
 
   @property
-  def generation_system(self) -> GenerationSystem:
+  def generation_system(self) -> List[GenerationSystem]:
     """
-    Get generation system
+    Get generation systems
     :return: GenerationSystem
     """
     return self._generation_system
diff --git a/hub/city_model_structure/energy_systems/generation_system.py b/hub/city_model_structure/energy_systems/generation_system.py
index 1561e370..10572805 100644
--- a/hub/city_model_structure/energy_systems/generation_system.py
+++ b/hub/city_model_structure/energy_systems/generation_system.py
@@ -22,6 +22,13 @@ class GenerationSystem:
     self._storage_capacity = None
     self._generic_generation_system = None
     self._auxiliary_equipment = None
+    self._model_name = None
+    self._manufacturer = None
+    self._maximum_heat_output = None
+    self._minimum_heat_output = None
+    self._maximum_cooling_output = None
+    self._minimum_cooling_output = None
+
 
   @property
   def generic_generation_system(self) -> GenericGenerationSystem:
diff --git a/hub/city_model_structure/energy_systems/generic_generation_system.py b/hub/city_model_structure/energy_systems/generic_generation_system.py
index 28094571..fa885a3c 100644
--- a/hub/city_model_structure/energy_systems/generic_generation_system.py
+++ b/hub/city_model_structure/energy_systems/generic_generation_system.py
@@ -24,6 +24,18 @@ class GenericGenerationSystem:
     self._source_mass_flow = None
     self._storage = None
     self._auxiliary_equipment = None
+    self._source_medium = None
+    self._supply_medium = None
+    self._maximum_heat_supply_temperature = None
+    self._minimum_heat_supply_temperature = None
+    self._maximum_cooling_supply_temperature = None
+    self._minimum_cooling_supply_temperature = None
+    self._heat_output_curve = None
+    self._heat_fuel_consumption_curve = None
+    self._heat_efficiency_curve = None
+    self._cooling_output_curve = None
+    self._cooling_fuel_consumption_curve = None
+    self._cooling_efficiency_curve = None
 
   @property
   def type(self):
@@ -184,3 +196,35 @@ class GenericGenerationSystem:
     :return: GenerationSystem
     """
     self._auxiliary_equipment = value
+
+  @property
+  def source_medium(self):
+    """
+    Get the source medium [air, water, ground, district_heating, grid, on_site_electricity]
+    :return: string
+    """
+    return self._source_medium
+
+  @source_medium.setter
+  def source_medium(self, value):
+    """
+    Set the source medium [air, water, ground, district_heating, grid, on_site_electricity]
+    :param value: string
+    """
+    self._source_medium = value
+
+  @property
+  def supply_medium(self):
+    """
+    Get the supply medium from ['air', 'water']
+    :return: string
+    """
+    return self._supply_medium
+
+  @supply_medium.setter
+  def supply_medium(self, value):
+    """
+    Set the supply medium from ['air', 'water']
+    :param value: string
+    """
+    self._supply_medium = value