diff --git a/config/co2eq_parameters.json b/config/co2eq_parameters.json
index 03526c952cc..766cf5b3fb6 100644
--- a/config/co2eq_parameters.json
+++ b/config/co2eq_parameters.json
@@ -582,6 +582,11 @@
         "hydro discharge": {
           "source": "2017 average by Tomorrow",
           "value": 462.73049119238584
+        },
+        "unknown": {
+          "_url": "https://github.com/tmrowco/electricitymap-contrib/issues/2804#issuecomment-750944105",
+          "source": "CBS 2019 & ENTSO-E. Assumes 67.5% gas, 18.1% biomass, 5% oil, 0.3% hydro, rest unknown equivalent",
+          "value": 468
         }
       },
       "NO-NO1": {