Grünstromindex: fall back to co2_g_oekostrom when co2_g_standard is null (#33164)

tariff/corrently/types.go

@@ -18,8 +18,8 @@ type Forecast struct {
 		Gsi           float64 `json:"gsi"`
 		TimeStamp     int64   `json:"timeStamp"`
 		Energyprice   string  `json:"energyprice"`
-		Co2GStandard  int     `json:"co2_g_standard"`
-		Co2GOekostrom int     `json:"co2_g_oekostrom"`
+		Co2GStandard  *int    `json:"co2_g_standard"`
+		Co2GOekostrom *int    `json:"co2_g_oekostrom"`
 		Timeframe     struct {
 			Start int64 `json:"start"`
 			End   int64 `json:"end"`

tariff/gruenstromindex.go

@@ -74,6 +74,13 @@ func (t *GrünStromIndex) run(done chan error) {
 			}
 		}
 
+		var data api.Rates
+		if err == nil {
+			if data = gsiRates(res); len(data) == 0 {
+				err = api.ErrNotAvailable
+			}
+		}
+
 		if err != nil {
 			if reportError(&once, done, err) {
 				return
@@ -83,20 +90,33 @@ func (t *GrünStromIndex) run(done chan error) {
 			continue
 		}
 
-		data := make(api.Rates, 0, len(res.Forecast))
-		for _, r := range res.Forecast {
-			data = append(data, api.Rate{
-				Start: time.UnixMilli(r.Timeframe.Start).Local(),
-				End:   time.UnixMilli(r.Timeframe.End).Local(),
-				Value: float64(r.Co2GStandard),
-			})
-		}
-
 		mergeRates(t.data, data)
 		once.Do(func() { close(done) })
 	}
 }
 
+// gsiRates maps the forecast to rates. co2_g_standard is null since mid-2026,
+// fall back to co2_g_oekostrom and skip slots without either value.
+func gsiRates(res corrently.Forecast) api.Rates {
+	data := make(api.Rates, 0, len(res.Forecast))
+	for _, r := range res.Forecast {
+		co2 := r.Co2GStandard
+		if co2 == nil {
+			co2 = r.Co2GOekostrom
+		}
+		if co2 == nil {
+			continue
+		}
+
+		data = append(data, api.Rate{
+			Start: time.UnixMilli(r.Timeframe.Start).Local(),
+			End:   time.UnixMilli(r.Timeframe.End).Local(),
+			Value: float64(*co2),
+		})
+	}
+	return data
+}
+
 // Rates implements the api.Tariff interface
 func (t *GrünStromIndex) Rates() (api.Rates, error) {
 	var res api.Rates

tariff/gruenstromindex_test.go

@@ -0,0 +1,25 @@
+package tariff
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/evcc-io/evcc/tariff/corrently"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGsiRates(t *testing.T) {
+	// co2_g_standard is null since mid-2026, co2_g_oekostrom is the fallback
+	var res corrently.Forecast
+	require.NoError(t, json.Unmarshal([]byte(`{"forecast":[
+		{"co2_g_standard":348,"co2_g_oekostrom":23,"timeframe":{"start":1787652000000,"end":1787655600000}},
+		{"co2_g_standard":null,"co2_g_oekostrom":25,"timeframe":{"start":1787655600000,"end":1787659200000}},
+		{"co2_g_standard":null,"co2_g_oekostrom":null,"timeframe":{"start":1787659200000,"end":1787662800000}}
+	]}`), &res))
+
+	rates := gsiRates(res)
+	require.Len(t, rates, 2)
+	assert.Equal(t, 348.0, rates[0].Value)
+	assert.Equal(t, 25.0, rates[1].Value)
+}