diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66c90485e5..71926d7f48 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -70,6 +70,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed grid within GridSpec test [#806](https://github.com/ie3-institute/simona/issues/806)
 - Fixed log entry after power flow calculation [#814](https://github.com/ie3-institute/simona/issues/814)
 - Delete "Indices and tables" on the index page [#375](https://github.com/ie3-institute/simona/issues/375)
+- Fixed provision of controllingEms within buildParticipantToActorRef [#841](https://github.com/ie3-institute/simona/issues/841)
 
 ## [3.0.0] - 2023-08-07
 
diff --git a/src/main/scala/edu/ie3/simona/agent/grid/GridAgentController.scala b/src/main/scala/edu/ie3/simona/agent/grid/GridAgentController.scala
index 7ba4abef77..43c111a47f 100644
--- a/src/main/scala/edu/ie3/simona/agent/grid/GridAgentController.scala
+++ b/src/main/scala/edu/ie3/simona/agent/grid/GridAgentController.scala
@@ -201,6 +201,18 @@ class GridAgentController(
       .map { participant =>
         val node = participant.getNode
 
+        val controllingEm =
+          participant.getControllingEm.toScala
+            .map(_.getUuid)
+            .map(uuid =>
+              allEms.getOrElse(
+                uuid,
+                throw new CriticalFailureException(
+                  s"EM actor with UUID $uuid not found."
+                ),
+              )
+            )
+
         val actorRef = buildParticipantActor(
           participantsConfig.requestVoltageDeviationThreshold,
           participantConfigUtil,
@@ -208,7 +220,7 @@ class GridAgentController(
           participant,
           thermalIslandGridsByBusId,
           environmentRefs,
-          allEms.get(participant.getUuid),
+          controllingEm,
         )
         introduceAgentToEnvironment(actorRef)
         // return uuid to actorRef