diff --git a/homeassistant/components/opower/sensor.py b/homeassistant/components/opower/sensor.py
index 1987abcc69d..2d8f1b5ded5 100644
--- a/homeassistant/components/opower/sensor.py
+++ b/homeassistant/components/opower/sensor.py
@@ -25,18 +25,13 @@ from .const import DOMAIN
 from .coordinator import OpowerCoordinator
 
 
-@dataclass(frozen=True)
-class OpowerEntityDescriptionMixin:
-    """Mixin values for required keys."""
+@dataclass(frozen=True, kw_only=True)
+class OpowerEntityDescription(SensorEntityDescription):
+    """Class describing Opower sensors entities."""
 
     value_fn: Callable[[Forecast], str | float]
 
 
-@dataclass(frozen=True)
-class OpowerEntityDescription(SensorEntityDescription, OpowerEntityDescriptionMixin):
-    """Class describing Opower sensors entities."""
-
-
 # suggested_display_precision=0 for all sensors since
 # Opower provides 0 decimal points for all these.
 # (for the statistics in the energy dashboard Opower does provide decimal points)