diff --git a/apps/predbat/solcast.py b/apps/predbat/solcast.py
index c24ca2838..9cc2f60da 100644
--- a/apps/predbat/solcast.py
+++ b/apps/predbat/solcast.py
@@ -511,7 +511,7 @@ def publish_pv_stats(self, pv_forecast_data, divide_by, period):
         power_now90 = 0
         power_nowCL = 0
 
-        point_gap = 30
+        point_gap = period
         for entry in pv_forecast_data:
             if "period_start" not in entry:
                 continue
@@ -887,12 +887,40 @@ async def fetch_pv_forecast(self):
             # We want to divide the data into single minute slots
             divide_by = dp2(30 * factor)
 
-            if factor != 1.0 and factor != 2.0:
+            # Valid factor values: 1.0 = kWh per slot (any interval), 2.0 = kW per 30-min slot, 4.0 = kW per 15-min slot
+            if factor not in [1.0, 2.0, 4.0]:
                 self.log("Warn: PV Forecast today adds up to {} kWh, but total sensors add up to {} kWh, this is unexpected and hence data maybe misleading (factor {})".format(pv_forecast_total_data, pv_forecast_total_sensor, factor))
             else:
                 self.log("PV Forecast today adds up to {} kWh, and total sensors add up to {} kWh, factor is {}".format(pv_forecast_total_data, pv_forecast_total_sensor, factor))
 
         if pv_forecast_data:
+            # Detect the actual period of the forecast data (e.g. 15 or 30 minutes)
+            # by examining the time difference between consecutive entries.
+            # This ensures 15-minute resolution data is handled correctly.
+            period = 30  # Default period in minutes
+            if len(pv_forecast_data) >= 2:
+                try:
+                    t0 = datetime.strptime(pv_forecast_data[0]["period_start"], TIME_FORMAT)
+                    t1 = datetime.strptime(pv_forecast_data[1]["period_start"], TIME_FORMAT)
+                    detected_period = int(abs((t1 - t0).total_seconds() / 60))
+                    # Sanity-check: only accept periods in the plausible range for forecast data.
+                    # Values outside 5–60 minutes (e.g. 1440 if the first two entries span a day
+                    # boundary when multiple sensor days are concatenated) are treated as invalid.
+                    if 5 <= detected_period <= 60:
+                        period = detected_period
+                except (ValueError, TypeError, KeyError):
+                    pass
+
+            # For the HA sensor path the divide_by was computed assuming 30-minute periods;
+            # recalculate it using the actual detected period so that the per-minute kWh
+            # values are correctly scaled regardless of the forecast resolution.
+            if not self.forecast_solar and not (self.solcast_host and self.solcast_api_key):
+                factor = divide_by / 30.0
+                divide_by = dp2(period * factor)
+
+            if period != 30:
+                self.log("PV Forecast data has {} minute resolution, adjusting calculations".format(period))
+
             pv_forecast_minute, _ = minute_data(
                 pv_forecast_data,
                 self.forecast_days,
@@ -902,7 +930,7 @@ async def fetch_pv_forecast(self):
                 backwards=False,
                 divide_by=divide_by,
                 scale=self.pv_scaling,
-                spreading=30,
+                spreading=period,
             )
             pv_forecast_minute10, _ = minute_data(
                 pv_forecast_data,
@@ -913,12 +941,12 @@ async def fetch_pv_forecast(self):
                 backwards=False,
                 divide_by=divide_by,
                 scale=self.pv_scaling,
-                spreading=30,
+                spreading=period,
             )
 
             # Run calibration on the data
-            pv_forecast_minute, pv_forecast_minute10, pv_forecast_data = self.pv_calibration(pv_forecast_minute, pv_forecast_minute10, pv_forecast_data, create_pv10, divide_by / 30.0, max_kwh)
-            self.publish_pv_stats(pv_forecast_data, divide_by / 30.0, 30)
+            pv_forecast_minute, pv_forecast_minute10, pv_forecast_data = self.pv_calibration(pv_forecast_minute, pv_forecast_minute10, pv_forecast_data, create_pv10, divide_by / period, max_kwh)
+            self.publish_pv_stats(pv_forecast_data, divide_by / period, period)
             self.pack_and_store_forecast(pv_forecast_minute, pv_forecast_minute10)
             self.update_success_timestamp()
             self.last_fetched_timestamp = self.now_utc_exact
diff --git a/apps/predbat/tests/test_solcast.py b/apps/predbat/tests/test_solcast.py
index dad67e127..cb9703ffc 100644
--- a/apps/predbat/tests/test_solcast.py
+++ b/apps/predbat/tests/test_solcast.py
@@ -1387,6 +1387,188 @@ def create_mock_session(*args, **kwargs):
     return failed
 
 
+# ============================================================================
+# 15-minute resolution tests
+# ============================================================================
+
+
+def test_fetch_pv_forecast_ha_sensors_15min_kwh(my_predbat):
+    """
+    Integration test: fetch_pv_forecast using HA sensors with 15-minute kWh resolution data.
+    Verifies that the energy totals are correct (not halved) when 15-minute data is used.
+    Each pv_estimate entry is in kWh for the 15-minute period.
+    """
+    print("  - test_fetch_pv_forecast_ha_sensors_15min_kwh")
+    failed = False
+
+    test_api = create_test_solar_api()
+    try:
+        test_api.solar.solcast_host = None
+        test_api.solar.solcast_api_key = None
+        test_api.solar.forecast_solar = None
+        test_api.solar.pv_forecast_today = "sensor.pv_forecast_today"
+        test_api.solar.pv_forecast_tomorrow = None
+
+        # 15-minute resolution data - pv_estimate is kWh per 15-min slot
+        # 4 slots of 0.25 kWh each = 1.0 kWh total (matching sensor state)
+        forecast_data_15min = [
+            {"period_start": "2025-06-15T10:00:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T10:15:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T10:30:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T10:45:00+0000", "pv_estimate": 0.25},
+        ]
+        # Sensor state = total daily kWh = 1.0
+        test_api.set_mock_ha_state(
+            "sensor.pv_forecast_today",
+            {
+                "state": "1.0",
+                "detailedForecast": forecast_data_15min,
+            },
+        )
+
+        def create_mock_session(*args, **kwargs):
+            return test_api.mock_aiohttp_session()
+
+        with patch("solcast.aiohttp.ClientSession", side_effect=create_mock_session):
+            run_async(test_api.solar.fetch_pv_forecast())
+
+        # Verify dashboard items were published
+        today_entity = f"sensor.{test_api.mock_base.prefix}_pv_today"
+        if today_entity not in test_api.dashboard_items:
+            print(f"ERROR: Expected {today_entity} to be published")
+            failed = True
+        else:
+            today_item = test_api.dashboard_items[today_entity]
+            total = today_item["attributes"].get("total", 0)
+            # Total should be 4 * 0.25 = 1.0 kWh, NOT 0.5 kWh (which would indicate the bug)
+            expected_total = 1.0
+            if abs(total - expected_total) > 0.05:
+                print(f"ERROR: Expected today total ~{expected_total} kWh with 15-min data, got {total} kWh (possible 15-min handling bug)")
+                failed = True
+            else:
+                print(f"  15-min kWh data: total={total} kWh (expected {expected_total}) - correct!")
+
+        # Verify forecast_raw entity was published
+        if f"sensor.{test_api.mock_base.prefix}_pv_forecast_raw" not in test_api.dashboard_items:
+            print(f"ERROR: Expected pv_forecast_raw entity to be published")
+            failed = True
+
+    finally:
+        test_api.cleanup()
+
+    return failed
+
+
+def test_fetch_pv_forecast_ha_sensors_15min_kw(my_predbat):
+    """
+    Integration test: fetch_pv_forecast using HA sensors with 15-minute kW resolution data.
+    Verifies that energy totals are correct when pv_estimate is in kW (new Solcast style)
+    with 15-minute period resolution.
+    """
+    print("  - test_fetch_pv_forecast_ha_sensors_15min_kw")
+    failed = False
+
+    test_api = create_test_solar_api()
+    try:
+        test_api.solar.solcast_host = None
+        test_api.solar.solcast_api_key = None
+        test_api.solar.forecast_solar = None
+        test_api.solar.pv_forecast_today = "sensor.pv_forecast_today"
+        test_api.solar.pv_forecast_tomorrow = None
+
+        # 15-minute resolution data - pv_estimate is kW (power), not kWh
+        # 4 slots of 1.0 kW each = 4 * 0.25h * 1.0 kW = 1.0 kWh total
+        # sum(pv_estimates) = 4.0, sensor state = 1.0 kWh => factor = 4.0
+        forecast_data_15min_kw = [
+            {"period_start": "2025-06-15T10:00:00+0000", "pv_estimate": 1.0},
+            {"period_start": "2025-06-15T10:15:00+0000", "pv_estimate": 1.0},
+            {"period_start": "2025-06-15T10:30:00+0000", "pv_estimate": 1.0},
+            {"period_start": "2025-06-15T10:45:00+0000", "pv_estimate": 1.0},
+        ]
+        # Sensor state = total daily kWh = 1.0
+        test_api.set_mock_ha_state(
+            "sensor.pv_forecast_today",
+            {
+                "state": "1.0",
+                "detailedForecast": forecast_data_15min_kw,
+            },
+        )
+
+        def create_mock_session(*args, **kwargs):
+            return test_api.mock_aiohttp_session()
+
+        with patch("solcast.aiohttp.ClientSession", side_effect=create_mock_session):
+            run_async(test_api.solar.fetch_pv_forecast())
+
+        today_entity = f"sensor.{test_api.mock_base.prefix}_pv_today"
+        if today_entity not in test_api.dashboard_items:
+            print(f"ERROR: Expected {today_entity} to be published")
+            failed = True
+        else:
+            today_item = test_api.dashboard_items[today_entity]
+            total = today_item["attributes"].get("total", 0)
+            # Total should be 1.0 kWh (4 slots * 1.0 kW * 0.25h), NOT 0.5 kWh
+            expected_total = 1.0
+            if abs(total - expected_total) > 0.05:
+                print(f"ERROR: Expected today total ~{expected_total} kWh with 15-min kW data, got {total} kWh (possible 15-min handling bug)")
+                failed = True
+            else:
+                print(f"  15-min kW data: total={total} kWh (expected {expected_total}) - correct!")
+
+        if f"sensor.{test_api.mock_base.prefix}_pv_forecast_raw" not in test_api.dashboard_items:
+            print(f"ERROR: Expected pv_forecast_raw entity to be published")
+            failed = True
+
+    finally:
+        test_api.cleanup()
+
+    return failed
+
+
+def test_publish_pv_stats_15min_resolution(my_predbat):
+    """
+    Test publish_pv_stats with 15-minute period data correctly uses point_gap=15
+    and computes totals correctly.
+    """
+    print("  - test_publish_pv_stats_15min_resolution")
+    failed = False
+
+    test_api = create_test_solar_api()
+    try:
+        # 15-minute resolution data - divide_by=1.0, period=15
+        # pv_estimate already in kWh per slot: 0.25 kWh each
+        pv_forecast_data = [
+            {"period_start": "2025-06-15T06:00:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T06:15:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T06:30:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T06:45:00+0000", "pv_estimate": 0.25},
+            {"period_start": "2025-06-15T12:00:00+0000", "pv_estimate": 0.5},
+            {"period_start": "2025-06-15T12:15:00+0000", "pv_estimate": 0.5},
+        ]
+
+        test_api.solar.publish_pv_stats(pv_forecast_data, divide_by=1.0, period=15)
+
+        today_entity = f"sensor.{test_api.mock_base.prefix}_pv_today"
+        if today_entity not in test_api.dashboard_items:
+            print(f"ERROR: Expected {today_entity} to be published")
+            failed = True
+        else:
+            today_item = test_api.dashboard_items[today_entity]
+            total = today_item["attributes"].get("total", 0)
+            # Total = 4*0.25 + 2*0.5 = 1.0 + 1.0 = 2.0 kWh
+            expected_total = 2.0
+            if abs(total - expected_total) > 0.05:
+                print(f"ERROR: Expected today total ~{expected_total}, got {total}")
+                failed = True
+            else:
+                print(f"  publish_pv_stats 15-min: total={total} kWh (expected {expected_total}) - correct!")
+
+    finally:
+        test_api.cleanup()
+
+    return failed
+
+
 # ============================================================================
 # Run Function Tests
 # ============================================================================
@@ -1659,4 +1841,9 @@ def run_solcast_tests(my_predbat):
     failed |= test_fetch_pv_forecast_forecast_solar(my_predbat)
     failed |= test_fetch_pv_forecast_ha_sensors(my_predbat)
 
+    # 15-minute resolution tests
+    failed |= test_fetch_pv_forecast_ha_sensors_15min_kwh(my_predbat)
+    failed |= test_fetch_pv_forecast_ha_sensors_15min_kw(my_predbat)
+    failed |= test_publish_pv_stats_15min_resolution(my_predbat)
+
     return failed