diff --git a/homeassistant/components/powerwall/__init__.py b/homeassistant/components/powerwall/__init__.py
index 57ae6f0e260..c6c508136b2 100644
--- a/homeassistant/components/powerwall/__init__.py
+++ b/homeassistant/components/powerwall/__init__.py
@@ -9,8 +9,9 @@ import voluptuous as vol
 
 from homeassistant.config_entries import SOURCE_IMPORT, ConfigEntry
 from homeassistant.const import CONF_IP_ADDRESS
-from homeassistant.core import HomeAssistant
+from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import ConfigEntryNotReady
+from homeassistant.helpers import entity_registry
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator
 
@@ -20,6 +21,7 @@ from .const import (
     POWERWALL_API_DEVICE_TYPE,
     POWERWALL_API_GRID_STATUS,
     POWERWALL_API_METERS,
+    POWERWALL_API_SERIAL_NUMBERS,
     POWERWALL_API_SITE_INFO,
     POWERWALL_API_SITEMASTER,
     POWERWALL_API_STATUS,
@@ -55,6 +57,36 @@ async def async_setup(hass: HomeAssistant, config: dict):
     return True
 
 
+async def _migrate_old_unique_ids(hass, entry_id, powerwall_data):
+    serial_numbers = powerwall_data[POWERWALL_API_SERIAL_NUMBERS]
+    site_info = powerwall_data[POWERWALL_API_SITE_INFO]
+
+    @callback
+    def _async_migrator(entity_entry: entity_registry.RegistryEntry):
+        parts = entity_entry.unique_id.split("_")
+        # Check if the unique_id starts with the serial_numbers of the powerwakks
+        if parts[0 : len(serial_numbers)] != serial_numbers:
+            # The old unique_id ended with the nomianal_system_engery_kWh so we can use that
+            # to find the old base unique_id and extract the device_suffix.
+            normalized_energy_index = (
+                len(parts)
+                - 1
+                - parts[::-1].index(str(site_info.nominal_system_energy_kWh))
+            )
+            device_suffix = parts[normalized_energy_index + 1 :]
+
+            new_unique_id = "_".join([*serial_numbers, *device_suffix])
+            _LOGGER.info(
+                "Migrating unique_id from [%s] to [%s]",
+                entity_entry.unique_id,
+                new_unique_id,
+            )
+            return {"new_unique_id": new_unique_id}
+        return None
+
+    await entity_registry.async_migrate_entries(hass, entry_id, _async_migrator)
+
+
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry):
     """Set up Tesla Powerwall from a config entry."""
 
@@ -69,6 +101,8 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry):
         http_session.close()
         raise ConfigEntryNotReady
 
+    await _migrate_old_unique_ids(hass, entry_id, powerwall_data)
+
     async def async_update_data():
         """Fetch data from API endpoint."""
         return await hass.async_add_executor_job(_fetch_powerwall_data, power_wall)
@@ -102,10 +136,14 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry):
 
 def call_base_info(power_wall):
     """Wrap powerwall properties to be a callable."""
+    serial_numbers = power_wall.get_serial_numbers()
+    # Make sure the serial numbers always have the same order
+    serial_numbers.sort()
     return {
         POWERWALL_API_SITE_INFO: power_wall.get_site_info(),
         POWERWALL_API_STATUS: power_wall.get_status(),
         POWERWALL_API_DEVICE_TYPE: power_wall.get_device_type(),
+        POWERWALL_API_SERIAL_NUMBERS: serial_numbers,
     }
 
 
diff --git a/homeassistant/components/powerwall/binary_sensor.py b/homeassistant/components/powerwall/binary_sensor.py
index f088a257574..4e1c639aa65 100644
--- a/homeassistant/components/powerwall/binary_sensor.py
+++ b/homeassistant/components/powerwall/binary_sensor.py
@@ -16,6 +16,7 @@ from .const import (
     DOMAIN,
     POWERWALL_API_DEVICE_TYPE,
     POWERWALL_API_GRID_STATUS,
+    POWERWALL_API_SERIAL_NUMBERS,
     POWERWALL_API_SITE_INFO,
     POWERWALL_API_SITEMASTER,
     POWERWALL_API_STATUS,
@@ -34,6 +35,7 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
     site_info = powerwall_data[POWERWALL_API_SITE_INFO]
     device_type = powerwall_data[POWERWALL_API_DEVICE_TYPE]
     status = powerwall_data[POWERWALL_API_STATUS]
+    powerwalls_serial_numbers = powerwall_data[POWERWALL_API_SERIAL_NUMBERS]
 
     entities = []
     for sensor_class in (
@@ -41,7 +43,11 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
         PowerWallGridStatusSensor,
         PowerWallConnectedSensor,
     ):
-        entities.append(sensor_class(coordinator, site_info, status, device_type))
+        entities.append(
+            sensor_class(
+                coordinator, site_info, status, device_type, powerwalls_serial_numbers
+            )
+        )
 
     async_add_entities(entities, True)
 
diff --git a/homeassistant/components/powerwall/const.py b/homeassistant/components/powerwall/const.py
index d05e42f6bf7..9f652bea5f5 100644
--- a/homeassistant/components/powerwall/const.py
+++ b/homeassistant/components/powerwall/const.py
@@ -34,6 +34,7 @@ POWERWALL_API_SITEMASTER = "sitemaster"
 POWERWALL_API_STATUS = "status"
 POWERWALL_API_DEVICE_TYPE = "device_type"
 POWERWALL_API_SITE_INFO = "site_info"
+POWERWALL_API_SERIAL_NUMBERS = "serial_numbers"
 
 POWERWALL_HTTP_SESSION = "http_session"
 
diff --git a/homeassistant/components/powerwall/entity.py b/homeassistant/components/powerwall/entity.py
index 9e09ed06c4b..27c12ed23ce 100644
--- a/homeassistant/components/powerwall/entity.py
+++ b/homeassistant/components/powerwall/entity.py
@@ -8,20 +8,17 @@ from .const import DOMAIN, MANUFACTURER, MODEL
 class PowerWallEntity(Entity):
     """Base class for powerwall entities."""
 
-    def __init__(self, coordinator, site_info, status, device_type):
+    def __init__(
+        self, coordinator, site_info, status, device_type, powerwalls_serial_numbers
+    ):
         """Initialize the sensor."""
         super().__init__()
         self._coordinator = coordinator
         self._site_info = site_info
         self._device_type = device_type
         self._version = status.version
-        # This group of properties will be unique to to the site
-        unique_group = (
-            site_info.utility,
-            site_info.grid_code,
-            str(site_info.nominal_system_energy_kWh),
-        )
-        self.base_unique_id = "_".join(unique_group)
+        # The serial numbers of the powerwalls are unique to every site
+        self.base_unique_id = "_".join(powerwalls_serial_numbers)
 
     @property
     def device_info(self):
diff --git a/homeassistant/components/powerwall/sensor.py b/homeassistant/components/powerwall/sensor.py
index 3b3d3b9cd32..253fae8bd36 100644
--- a/homeassistant/components/powerwall/sensor.py
+++ b/homeassistant/components/powerwall/sensor.py
@@ -19,6 +19,7 @@ from .const import (
     POWERWALL_API_CHARGE,
     POWERWALL_API_DEVICE_TYPE,
     POWERWALL_API_METERS,
+    POWERWALL_API_SERIAL_NUMBERS,
     POWERWALL_API_SITE_INFO,
     POWERWALL_API_STATUS,
     POWERWALL_COORDINATOR,
@@ -37,14 +38,26 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
     site_info = powerwall_data[POWERWALL_API_SITE_INFO]
     device_type = powerwall_data[POWERWALL_API_DEVICE_TYPE]
     status = powerwall_data[POWERWALL_API_STATUS]
+    powerwalls_serial_numbers = powerwall_data[POWERWALL_API_SERIAL_NUMBERS]
 
     entities = []
     for meter in MeterType:
         entities.append(
-            PowerWallEnergySensor(meter, coordinator, site_info, status, device_type)
+            PowerWallEnergySensor(
+                meter,
+                coordinator,
+                site_info,
+                status,
+                device_type,
+                powerwalls_serial_numbers,
+            )
         )
 
-    entities.append(PowerWallChargeSensor(coordinator, site_info, status, device_type))
+    entities.append(
+        PowerWallChargeSensor(
+            coordinator, site_info, status, device_type, powerwalls_serial_numbers
+        )
+    )
 
     async_add_entities(entities, True)
 
@@ -81,9 +94,19 @@ class PowerWallChargeSensor(PowerWallEntity):
 class PowerWallEnergySensor(PowerWallEntity):
     """Representation of an Powerwall Energy sensor."""
 
-    def __init__(self, meter: MeterType, coordinator, site_info, status, device_type):
+    def __init__(
+        self,
+        meter: MeterType,
+        coordinator,
+        site_info,
+        status,
+        device_type,
+        powerwalls_serial_numbers,
+    ):
         """Initialize the sensor."""
-        super().__init__(coordinator, site_info, status, device_type)
+        super().__init__(
+            coordinator, site_info, status, device_type, powerwalls_serial_numbers
+        )
         self._meter = meter
 
     @property
diff --git a/tests/components/powerwall/mocks.py b/tests/components/powerwall/mocks.py
index afe9e130379..8a559d1dd49 100644
--- a/tests/components/powerwall/mocks.py
+++ b/tests/components/powerwall/mocks.py
@@ -36,6 +36,7 @@ async def _mock_powerwall_with_fixtures(hass):
         grid_status=GridStatus.CONNECTED,
         status=PowerwallStatusResponse(status),
         device_type=DeviceType(device_type["device_type"]),
+        serial_numbers=["TG0123456789AB", "TG9876543210BA"],
     )
 
 
@@ -47,6 +48,7 @@ def _mock_powerwall_return_value(
     grid_status=None,
     status=None,
     device_type=None,
+    serial_numbers=None,
 ):
     powerwall_mock = MagicMock(Powerwall("1.2.3.4"))
     powerwall_mock.get_site_info = Mock(return_value=site_info)
@@ -56,6 +58,7 @@ def _mock_powerwall_return_value(
     powerwall_mock.get_grid_status = Mock(return_value=grid_status)
     powerwall_mock.get_status = Mock(return_value=status)
     powerwall_mock.get_device_type = Mock(return_value=device_type)
+    powerwall_mock.get_serial_numbers = Mock(return_value=serial_numbers)
 
     return powerwall_mock
 
diff --git a/tests/components/powerwall/test_sensor.py b/tests/components/powerwall/test_sensor.py
index ce0c929ab92..b6c224080a1 100644
--- a/tests/components/powerwall/test_sensor.py
+++ b/tests/components/powerwall/test_sensor.py
@@ -25,8 +25,7 @@ async def test_sensors(hass):
 
     device_registry = await hass.helpers.device_registry.async_get_registry()
     reg_device = device_registry.async_get_device(
-        identifiers={("powerwall", "Wom Energy_60Hz_240V_s_IEEE1547a_2014_13.5")},
-        connections=set(),
+        identifiers={("powerwall", "TG0123456789AB_TG9876543210BA")}, connections=set(),
     )
     assert reg_device.model == "PowerWall 2 (GW1)"
     assert reg_device.sw_version == "1.45.1"