diff --git a/homeassistant/components/watttime/config_flow.py b/homeassistant/components/watttime/config_flow.py
index f479ec69630b..51f099e7d319 100644
--- a/homeassistant/components/watttime/config_flow.py
+++ b/homeassistant/components/watttime/config_flow.py
@@ -145,7 +145,7 @@ class WattTimeConfigFlow(ConfigFlow, domain=DOMAIN):
 
         try:
             grid_region = await self._client.emissions.async_get_grid_region(
-                user_input[CONF_LATITUDE], user_input[CONF_LONGITUDE]
+                user_input[CONF_LATITUDE], user_input[CONF_LONGITUDE], "co2_moer"
             )
         except CoordinatesNotFoundError:
             return self.async_show_form(
@@ -168,8 +168,8 @@ class WattTimeConfigFlow(ConfigFlow, domain=DOMAIN):
                 CONF_PASSWORD: self._data[CONF_PASSWORD],
                 CONF_LATITUDE: user_input[CONF_LATITUDE],
                 CONF_LONGITUDE: user_input[CONF_LONGITUDE],
-                CONF_BALANCING_AUTHORITY: grid_region["name"],
-                CONF_BALANCING_AUTHORITY_ABBREV: grid_region["abbrev"],
+                CONF_BALANCING_AUTHORITY: grid_region["region_full_name"],
+                CONF_BALANCING_AUTHORITY_ABBREV: grid_region["region"],
             },
         )
 
diff --git a/homeassistant/components/watttime/coordinator.py b/homeassistant/components/watttime/coordinator.py
index b52a986ee96d..e9da03746710 100644
--- a/homeassistant/components/watttime/coordinator.py
+++ b/homeassistant/components/watttime/coordinator.py
@@ -4,23 +4,23 @@ from datetime import timedelta
 from typing import override
 
 from aiowatttime import Client
-from aiowatttime.emissions import RealTimeEmissionsResponseType
 from aiowatttime.errors import InvalidCredentialsError, WattTimeError
 
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.const import CONF_LATITUDE, CONF_LONGITUDE
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import ConfigEntryAuthFailed
+from homeassistant.helpers.typing import StateType
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 
-from .const import DOMAIN, LOGGER
+from .const import CONF_BALANCING_AUTHORITY_ABBREV, DOMAIN, LOGGER
 
 DEFAULT_UPDATE_INTERVAL = timedelta(minutes=5)
 
+type WattTimeData = dict[str, StateType]
 type WattTimeConfigEntry = ConfigEntry[WattTimeCoordinator]
 
 
-class WattTimeCoordinator(DataUpdateCoordinator[RealTimeEmissionsResponseType]):
+class WattTimeCoordinator(DataUpdateCoordinator[WattTimeData]):
     """Coordinator for WattTime data updates."""
 
     config_entry: WattTimeConfigEntry
@@ -42,12 +42,11 @@ class WattTimeCoordinator(DataUpdateCoordinator[RealTimeEmissionsResponseType]):
         self.client = client
 
     @override
-    async def _async_update_data(self) -> RealTimeEmissionsResponseType:
+    async def _async_update_data(self) -> WattTimeData:
         """Get the latest realtime emissions data."""
         try:
-            return await self.client.emissions.async_get_realtime_emissions(
-                self.config_entry.data[CONF_LATITUDE],
-                self.config_entry.data[CONF_LONGITUDE],
+            data = await self.client.emissions.async_get_realtime_emissions(
+                self.config_entry.data[CONF_BALANCING_AUTHORITY_ABBREV]
             )
         except InvalidCredentialsError as err:
             raise ConfigEntryAuthFailed("Invalid username/password") from err
@@ -55,3 +54,5 @@ class WattTimeCoordinator(DataUpdateCoordinator[RealTimeEmissionsResponseType]):
             raise UpdateFailed(
                 f"Error while requesting data from WattTime: {err}"
             ) from err
+
+        return {"percent": data["data"][0]["value"]}
diff --git a/homeassistant/components/watttime/manifest.json b/homeassistant/components/watttime/manifest.json
index 3abe910b9b0e..eafc24d0c91f 100644
--- a/homeassistant/components/watttime/manifest.json
+++ b/homeassistant/components/watttime/manifest.json
@@ -7,5 +7,5 @@
   "integration_type": "service",
   "iot_class": "cloud_polling",
   "loggers": ["aiowatttime"],
-  "requirements": ["aiowatttime==0.1.1"]
+  "requirements": ["aiowatttime==2024.6.0"]
 }
diff --git a/homeassistant/components/watttime/sensor.py b/homeassistant/components/watttime/sensor.py
index cb78e17031d0..5eb6b1f4f5a9 100644
--- a/homeassistant/components/watttime/sensor.py
+++ b/homeassistant/components/watttime/sensor.py
@@ -1,7 +1,7 @@
 """Support for WattTime sensors."""
 
 from collections.abc import Mapping
-from typing import Any, cast, override
+from typing import Any, override
 
 from homeassistant.components.sensor import (
     SensorEntity,
@@ -110,4 +110,4 @@ class RealtimeEmissionsSensor(CoordinatorEntity[WattTimeCoordinator], SensorEnti
     @override
     def native_value(self) -> StateType:
         """Return the value reported by the sensor."""
-        return cast(StateType, self.coordinator.data[self.entity_description.key])
+        return self.coordinator.data[self.entity_description.key]
diff --git a/requirements_all.txt b/requirements_all.txt
index ffc67f3b66dc..7486abb83188 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -480,7 +480,7 @@ aiovodafone==3.3.2
 aiowaqi==3.1.0
 
 # homeassistant.components.watttime
-aiowatttime==0.1.1
+aiowatttime==2024.6.0
 
 # homeassistant.components.webdav
 aiowebdav2==0.6.2
diff --git a/tests/components/watttime/fixtures/grid_region_data.json b/tests/components/watttime/fixtures/grid_region_data.json
index 0104ebeb98c8..ef8341103010 100644
--- a/tests/components/watttime/fixtures/grid_region_data.json
+++ b/tests/components/watttime/fixtures/grid_region_data.json
@@ -1,5 +1,5 @@
 {
-  "id": 263,
-  "abbrev": "PJM_NJ",
-  "name": "PJM New Jersey"
+  "region": "PJM_NJ",
+  "region_full_name": "PJM New Jersey",
+  "signal_type": "co2_moer"
 }
diff --git a/tests/components/watttime/fixtures/realtime_emissions_data.json b/tests/components/watttime/fixtures/realtime_emissions_data.json
index d11476bc8705..f034b8f88f58 100644
--- a/tests/components/watttime/fixtures/realtime_emissions_data.json
+++ b/tests/components/watttime/fixtures/realtime_emissions_data.json
@@ -1,7 +1,11 @@
 {
-  "freq": "300",
-  "ba": "CAISO_NORTH",
-  "percent": "53",
-  "moer": "850.743982",
-  "point_time": "2019-01-29T14:55:00.00Z"
+  "data": [{ "point_time": "2024-06-18T18:40:00+00:00", "value": 96.0 }],
+  "meta": {
+    "data_point_period_seconds": 300,
+    "region": "PJM_NJ",
+    "signal_type": "co2_moer",
+    "units": "percentile",
+    "warnings": [],
+    "model": { "date": "2022-10-01" }
+  }
 }
diff --git a/tests/components/watttime/snapshots/test_diagnostics.ambr b/tests/components/watttime/snapshots/test_diagnostics.ambr
index 3cc5e1d6f66b..ddeefc914ba8 100644
--- a/tests/components/watttime/snapshots/test_diagnostics.ambr
+++ b/tests/components/watttime/snapshots/test_diagnostics.ambr
@@ -2,11 +2,7 @@
 # name: test_entry_diagnostics
   dict({
     'data': dict({
-      'ba': 'CAISO_NORTH',
-      'freq': '300',
-      'moer': '850.743982',
-      'percent': '53',
-      'point_time': '2019-01-29T14:55:00.00Z',
+      'percent': 96.0,
     }),
     'entry': dict({
       'data': dict({