feat: add EnergyCharts feed-in tariff provider (#1165)

The `FeedInTariffEnergyCharts` provider uses the raw Energy-Charts day-ahead market price as the
feed-in tariff. It stores prices in `feed_in_tariff_wh` without adding electricity import charges
or VAT. The data is loaded from the Energy-Charts `/price` endpoint for the configured bidding
zone. The native Energy-Charts resolution, including quarter-hour data, is retained.

Energy-Charts usually supplies prices only for the published day-ahead period. If that data does
not cover the complete configured prediction horizon, the provider extends it as follows:

- With more than 800 hours of history, an ETS (Holt-Winters exponential smoothing) forecast with
  weekly seasonality is used.
- With more than 168 hours of history, an ETS forecast with daily seasonality is used.
- With less history, the median of the available values is used as a constant fallback.

The seasonal periods are adjusted to the source resolution. For example, quarter-hour data uses
four values per hour. Values already supplied by Energy-Charts are kept unchanged; only missing
future slots after the last published price are forecast. Consequently, a 15-minute optimization
uses four forecast values per hour without converting them to hourly averages.

Signed-off-by: Andreas Schmitz <akkudoktor.net>
Signed-off-by: Bobby Noelte <b0661n0e17e@gmail.com>

tests/test_prediction.py

@@ -7,6 +7,7 @@ from akkudoktoreos.prediction.elecpriceenergycharts import ElecPriceEnergyCharts
 from akkudoktoreos.prediction.elecpricefixed import ElecPriceFixed
 from akkudoktoreos.prediction.elecpriceimport import ElecPriceImport
 from akkudoktoreos.prediction.elecpricetibber import ElecPriceTibber
+from akkudoktoreos.prediction.feedintariffenergycharts import FeedInTariffEnergyCharts
 from akkudoktoreos.prediction.feedintarifffixed import FeedInTariffFixed
 from akkudoktoreos.prediction.feedintariffimport import FeedInTariffImport
 from akkudoktoreos.prediction.loadakkudoktor import (
@@ -46,6 +47,7 @@ def forecast_providers():
         ElecPriceFixed(),
         ElecPriceImport(),
         ElecPriceTibber(),
+        FeedInTariffEnergyCharts(),
         FeedInTariffFixed(),
         FeedInTariffImport(),
         LoadAkkudoktor(),
@@ -99,22 +101,23 @@ def test_provider_sequence(prediction):
     assert isinstance(prediction.providers[2], ElecPriceFixed)
     assert isinstance(prediction.providers[3], ElecPriceImport)
     assert isinstance(prediction.providers[4], ElecPriceTibber)
-    assert isinstance(prediction.providers[5], FeedInTariffFixed)
-    assert isinstance(prediction.providers[6], FeedInTariffImport)
-    assert isinstance(prediction.providers[7], LoadAkkudoktor)
-    assert isinstance(prediction.providers[8], LoadAkkudoktorAdjusted)
-    assert isinstance(prediction.providers[9], LoadVrm)
-    assert isinstance(prediction.providers[10], LoadImport)
-    assert isinstance(prediction.providers[11], PVForecastAkkudoktor)
-    assert isinstance(prediction.providers[12], PVForecastVrm)
-    assert isinstance(prediction.providers[13], PVForecastPVNode)
-    assert isinstance(prediction.providers[14], PVForecastForecastSolar)
-    assert isinstance(prediction.providers[15], PVForecastSolcast)
-    assert isinstance(prediction.providers[16], PVForecastImport)
-    assert isinstance(prediction.providers[17], WeatherBrightSky)
-    assert isinstance(prediction.providers[18], WeatherClearOutside)
-    assert isinstance(prediction.providers[19], WeatherOpenMeteo)
-    assert isinstance(prediction.providers[20], WeatherImport)
+    assert isinstance(prediction.providers[5], FeedInTariffEnergyCharts)
+    assert isinstance(prediction.providers[6], FeedInTariffFixed)
+    assert isinstance(prediction.providers[7], FeedInTariffImport)
+    assert isinstance(prediction.providers[8], LoadAkkudoktor)
+    assert isinstance(prediction.providers[9], LoadAkkudoktorAdjusted)
+    assert isinstance(prediction.providers[10], LoadVrm)
+    assert isinstance(prediction.providers[11], LoadImport)
+    assert isinstance(prediction.providers[12], PVForecastAkkudoktor)
+    assert isinstance(prediction.providers[13], PVForecastVrm)
+    assert isinstance(prediction.providers[14], PVForecastPVNode)
+    assert isinstance(prediction.providers[15], PVForecastForecastSolar)
+    assert isinstance(prediction.providers[16], PVForecastSolcast)
+    assert isinstance(prediction.providers[17], PVForecastImport)
+    assert isinstance(prediction.providers[18], WeatherBrightSky)
+    assert isinstance(prediction.providers[19], WeatherClearOutside)
+    assert isinstance(prediction.providers[20], WeatherOpenMeteo)
+    assert isinstance(prediction.providers[21], WeatherImport)
 
 
 def test_provider_by_id(prediction, forecast_providers):
@@ -132,6 +135,7 @@ def test_prediction_repr(prediction):
     assert "ElecPriceFixed" in result
     assert "ElecPriceImport" in result
     assert "ElecPriceTibber" in result
+    assert "FeedInTariffEnergyCharts" in result
     assert "FeedInTariffFixed" in result
     assert "FeedInTariffImport" in result
     assert "LoadAkkudoktor" in result