diff --git a/src/ert/simulator/batch_simulator.py b/src/ert/simulator/batch_simulator.py
index cf6438c73f8..75bf8d0474b 100644
--- a/src/ert/simulator/batch_simulator.py
+++ b/src/ert/simulator/batch_simulator.py
@@ -9,7 +9,7 @@
 from .batch_simulator_context import BatchContext
 
 if TYPE_CHECKING:
-    from ert.storage import Ensemble, Storage
+    from ert.storage import Ensemble, Experiment
 
 
 class BatchSimulator:
@@ -165,7 +165,7 @@ def start(
         self,
         case_name: str,
         case_data: List[Tuple[int, Dict[str, Dict[str, Any]]]],
-        storage: Storage,
+        experiment: Experiment,
     ) -> BatchContext:
         """Start batch simulation, return a simulation context
 
@@ -224,13 +224,7 @@ def start(
         time, so when you have called the 'start' method you need to let that
         batch complete before you start a new batch.
         """
-        experiment = storage.create_experiment(
-            parameters=self.ert_config.ensemble_config.parameter_configuration,
-            responses=self.ert_config.ensemble_config.response_configuration,
-            name=f"experiment_{case_name}",
-        )
-        ensemble = storage.create_ensemble(
-            experiment.id,
+        ensemble = experiment.create_ensemble(
             name=case_name,
             ensemble_size=self.ert_config.model_config.num_realizations,
         )
diff --git a/tests/unit_tests/simulator/test_batch_sim.py b/tests/unit_tests/simulator/test_batch_sim.py
index afb5bee124e..2bb555b8e85 100644
--- a/tests/unit_tests/simulator/test_batch_sim.py
+++ b/tests/unit_tests/simulator/test_batch_sim.py
@@ -142,8 +142,14 @@ def batch_simulator(batch_sim_example):
 def test_that_starting_with_invalid_key_raises_key_error(
     batch_simulator, _input, match, storage
 ):
+    experiment = storage.create_experiment(
+        name="EnOptCase",
+        parameters=batch_simulator.ert_config.ensemble_config.parameter_configuration,
+        responses=batch_simulator.ert_config.ensemble_config.response_configuration,
+    )
+
     with pytest.raises(KeyError, match=match):
-        batch_simulator.start("case", _input, storage)
+        batch_simulator.start("case", _input, experiment)
 
 
 def test_batch_simulation(batch_simulator, storage):
@@ -165,7 +171,13 @@ def test_batch_simulation(batch_simulator, storage):
         ),
     ]
 
-    ctx = batch_simulator.start("case", case_data, storage=storage)
+    experiment = storage.create_experiment(
+        name="EnOptCase",
+        parameters=batch_simulator.ert_config.ensemble_config.parameter_configuration,
+        responses=batch_simulator.ert_config.ensemble_config.response_configuration,
+    )
+
+    ctx = batch_simulator.start("case", case_data, experiment)
     assert len(case_data) == len(ctx.mask)
 
     # Asking for results before it is complete.
@@ -279,8 +291,15 @@ def test_that_batch_simulator_handles_invalid_suffixes_at_start(
         },
         ["ORDER"],
     )
+
+    experiment = storage.create_experiment(
+        name="EnOptCase",
+        parameters=batch_sim_example.ensemble_config.parameter_configuration,
+        responses=batch_sim_example.ensemble_config.response_configuration,
+    )
+
     with pytest.raises(KeyError, match=match):
-        rsim.start("case", inp, storage)
+        rsim.start("case", inp, experiment)
 
 
 @pytest.mark.usefixtures("use_tmpdir")
@@ -326,7 +345,13 @@ def test_batch_simulation_suffixes(batch_sim_example, storage):
         ),
     ]
 
-    ctx = rsim.start("case", case_data, storage=storage)
+    experiment = storage.create_experiment(
+        name="EnOptCase",
+        parameters=ert_config.ensemble_config.parameter_configuration,
+        responses=ert_config.ensemble_config.response_configuration,
+    )
+
+    ctx = rsim.start("case", case_data, experiment)
     assert len(case_data) == len(ctx)
     _wait_for_completion(ctx)
 
@@ -389,8 +414,14 @@ def test_stop_sim(copy_case, storage):
         ),
     ]
 
+    experiment = storage.create_experiment(
+        name="EnOptCase",
+        parameters=ert_config.ensemble_config.parameter_configuration,
+        responses=ert_config.ensemble_config.response_configuration,
+    )
+
     # Starting a simulation which should actually run through.
-    ctx = rsim.start(case_name, case_data, storage=storage)
+    ctx = rsim.start(case_name, case_data, experiment)
 
     ctx.stop()
     status = ctx.status
@@ -452,7 +483,13 @@ def test_batch_ctx_status_failing_jobs(setup_case, storage):
         for idx in range(10)
     ]
 
-    batch_ctx = rsim.start("case_name", ensembles, storage=storage)
+    experiment = storage.create_experiment(
+        name="EnOptCase",
+        parameters=ert_config.ensemble_config.parameter_configuration,
+        responses=ert_config.ensemble_config.response_configuration,
+    )
+
+    batch_ctx = rsim.start("case_name", ensembles, experiment)
     while batch_ctx.running():
         assertContextStatusOddFailures(batch_ctx)
         time.sleep(1)