diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index d466455..3bec7e4 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -6,7 +6,7 @@
 
 ## Upgrading
 
-<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+* Change the `curtailable` flag default of the PV config to `None`.
 
 ## New Features
 
diff --git a/src/frequenz/gridpool/_microgrid_config.py b/src/frequenz/gridpool/_microgrid_config.py
index d21deb6..b99e6d2 100644
--- a/src/frequenz/gridpool/_microgrid_config.py
+++ b/src/frequenz/gridpool/_microgrid_config.py
@@ -117,7 +117,7 @@ class PVConfig:
     rated_power: float | None = None
     """Rated power of the inverters in Watt."""
 
-    curtailable: bool = False
+    curtailable: bool | None = None
     """Flag to indicate if PV system can be curtailed."""