diff --git a/config/config.validation.yaml b/config/config.validation.yaml
index cb53d4d3..ea40dda3 100644
--- a/config/config.validation.yaml
+++ b/config/config.validation.yaml
@@ -25,7 +25,6 @@ scenario:
   - v1.0
   clusters:  # number of nodes in Europe, any integer between 37 (1 node per country-zone) and several hundred
   - 37
-  - "37c"
   # - 128
   # - 256
   # - 512
@@ -592,7 +591,7 @@ clustering:
     to_substations: false # network is simplified to nodes with positive or negative power injection (i.e. substations or offwind connections)
     algorithm: kmeans # choose from: [hac, kmeans]
     feature: solar+onwind-time # only for hac. choose from: [solar+onwind-time, solar+onwind-cap, solar-time, solar-cap, solar+offwind-cap] etc.
-    exclude_carriers: []
+    exclude_carriers: ['CCGT', 'lignite', 'oil', 'coal', 'OCGT', 'nuclear']
     remove_stubs: true
     remove_stubs_across_borders: true
   cluster_network: