diff --git a/scripts/add_electricity.py b/scripts/add_electricity.py
index eabe0459..1b913526 100755
--- a/scripts/add_electricity.py
+++ b/scripts/add_electricity.py
@@ -471,7 +471,7 @@ def attach_conventional_generators(
         **committable_attrs,
     )
 
-    for carrier in set(conventional_params) & carriers:
+    for carrier in set(conventional_params) & set(carriers):
         # Generators with technology affected
         idx = n.generators.query("carrier == @carrier").index