diff --git a/templates/definition/tariff/forecast-solar.yaml b/templates/definition/tariff/forecast-solar.yaml
index f7e6ccac4..27bfb2ad9 100644
--- a/templates/definition/tariff/forecast-solar.yaml
+++ b/templates/definition/tariff/forecast-solar.yaml
@@ -66,7 +66,7 @@ render: |
   tariff: solar
   forecast:
     source: http
-    uri: https://api.forecast.solar/{{ if .apikey }}{{ .apikey }}/{{ end }}estimate/{{ .lat }}/{{ .lon }}/{{ .dec }}/{{ .az }}/{{ .kwp }}?time=utc&full=1&resolution=60{{ if .horizon }}&horizon={{ .horizon }}{{ end }}
+    uri: https://api.forecast.solar/{{ if .apikey }}{{ .apikey }}/{{ end }}estimate/{{ .lat }}/{{ .lon }}/{{ .dec }}/{{ .az }}/{{ .kwp }}?time=utc&full=1&resolution=60{{ if .horizon }}&horizon={{ unquote .horizon }}{{ end }}
     jq: |
       [ .result.watts | to_entries.[] | {
         "start": (.key | strptime("%FT%T%z") | strftime("%FT%TZ")),
diff --git a/util/templates/utils.go b/util/templates/utils.go
index b63660806..b95bb555e 100644
--- a/util/templates/utils.go
+++ b/util/templates/utils.go
@@ -44,6 +44,10 @@ func trimLines(s string) string {
 	return strings.Join(lines, "\n")
 }
 
+func unquote(s string) string {
+	return strings.Trim(s, `"'`)
+}
+
 // FuncMap returns a sprig template.FuncMap with additional include function
 func FuncMap(tmpl *template.Template) *template.Template {
 	funcMap := template.FuncMap{
@@ -57,6 +61,7 @@ func FuncMap(tmpl *template.Template) *template.Template {
 			return buf.String(), nil
 		},
 		"urlEncode": url.QueryEscape,
+		"unquote":   unquote,
 	}
 
 	return tmpl.Funcs(sprig.FuncMap()).Funcs(funcMap)