diff --git a/ema_workbench/em_framework/util.py b/ema_workbench/em_framework/util.py
index 46912732d..950dccd3f 100644
--- a/ema_workbench/em_framework/util.py
+++ b/ema_workbench/em_framework/util.py
@@ -65,9 +65,7 @@ def variable_name(self, name):
 
     def __init__(self, name):
         if not name.isidentifier():
-            DeprecationWarning(
-                f"'{name}' is not a valid Python identifier. Starting from version 3.0 of the EMAworkbench, names must be valid python identifiers"
-            )
+            raise ValueError(f"'{name}' is not a valid Python identifier.")
         super().__init__(name)