diff --git a/src/energy_grid.F90 b/src/energy_grid.F90
index d2351c94cf..39f5fcd31f 100644
--- a/src/energy_grid.F90
+++ b/src/energy_grid.F90
@@ -99,7 +99,7 @@ contains
 
     ! if the original list is empty, we need to allocate the first element and
     ! store first energy point
-    if (list_size(list) == 0) then
+    if (.not. associated(list)) then
        allocate(list)
        current => list
        do i = 1, n