diff --git a/sdks/python/apache_beam/testing/load_tests/dataflow_cost_benchmark.py b/sdks/python/apache_beam/testing/load_tests/dataflow_cost_benchmark.py
index b60af1249756..96a1cd31e298 100644
--- a/sdks/python/apache_beam/testing/load_tests/dataflow_cost_benchmark.py
+++ b/sdks/python/apache_beam/testing/load_tests/dataflow_cost_benchmark.py
@@ -109,5 +109,7 @@ def _process_metrics_list(self,
       metric_key = entry.key
       metric = metric_key.metric
       if metric_key.step == '' and metric.namespace == 'dataflow/v1b3':
+        if entry.committed is None:
+          entry.committed = 0.0
         system_metrics[metric.name] = entry.committed
     return system_metrics