This could actually be working

custom_components/nordpool_planner/__init__.py

@@ -207,6 +207,7 @@ def __init__(self, hass: HomeAssistant, config_entry: ConfigEntry) -> None:
 
         # Local state variables
         self._last_update = None
+        self.low_hours = None
 
         # Output states
         self.low_cost_state = NordpoolPlannerState()
@@ -515,10 +516,12 @@ def update(self):
             )
             if self._is_static:
                 if self.low_cost_state.on_at(now):
-                    if counter := self._output_listeners.get(
-                        CONF_REMAINING_HOURS_ENTITY
-                    ):
-                        pass
+                    if self.low_hours is None:
+                        self.low_hours = 1
+                    else:
+                        self.low_hours += 1
+                if end_time.hour == now.hour:
+                    self.low_hours = 0
         self._last_update = now
 
     def set_lowest_cost_state(self, prices_group: NordpoolPricesGroup) -> None:

custom_components/nordpool_planner/sensor.py

@@ -178,24 +178,16 @@ async def async_added_to_hass(self) -> None:
         await super().async_added_to_hass()
         if (
             (last_state := await self.async_get_last_state()) is not None
-            and (extra_data := await self.async_get_last_sensor_data()) is not None
             and last_state.state not in (STATE_UNKNOWN, STATE_UNAVAILABLE)
-            # The trigger might have fired already while we waited for stored data,
-            # then we should not restore state
-
-            # and CONF_STATE not in self._rendered
+            # and (extra_data := await self.async_get_last_sensor_data()) is not None
         ):
-            # self._rendered[CONF_STATE] = extra_data.native_value
-            self.restore_attributes(last_state)
-
-            # ToDo: Call planner and set value there!
+            self._planner.low_hours = last_state.state
+        else:
+            # self._planner.low_hours = 0
+            pass
 
 
     @property
     def native_value(self):
         """Output state."""
-        state = None
-
-        # TODO: Add the logic
-
-        return state
+        return self._planner.low_hours