diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5d7867798..d644d45f2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ and the versioning aims to respect [Semantic Versioning](http://semver.org/spec/
 ## [1.X.X] - 20XX-XX-XX
 
 ### Added
+- oeo-import-edits as a unified file for custom extensions of imported concepts + properties (#1268)
 - tank, fuel tank, volume (#1356)
 - filling station, hydrogen station, hydrogen transport (#1357)
 - OEP user, qualitist, quantitist, apinist (#1383)
@@ -27,7 +28,7 @@ and the versioning aims to respect [Semantic Versioning](http://semver.org/spec/
 - rotary heat exchanger, plate heat exchanger, boiler, tube collector, flat-plate collector (#1432)
 - utilisation value (#1435)
 - amortisation time, economic life time (#1436)
-- oeo-import-edits as a unified file for custom extensions of imported concepts + properties (#1268)
+- energy transformation function and subclasses (#1445)
 
 ### Changed
 - internal combustion vehicle, plug-in hybrid electric vehicle, fuel cell electric vehicle, tank ship, gas turbine vehicle (#1356)
diff --git a/src/ontology/edits/oeo-physical.omn b/src/ontology/edits/oeo-physical.omn
index 711f43ac5..fecb03cb9 100644
--- a/src/ontology/edits/oeo-physical.omn
+++ b/src/ontology/edits/oeo-physical.omn
@@ -6462,6 +6462,57 @@ pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1409",
         OEO_00010336
     
     
+Class: OEO_00010385
+
+    Annotations: 
+        <http://purl.obolibrary.org/obo/IAO_0000115> "An energy transformation function is the function of an artificial object that has been engineered to transform input energy into usable output energy of a different type.",
+        <http://purl.obolibrary.org/obo/IAO_0000233> "issue: https://github.com/OpenEnergyPlatform/ontology/issues/1438
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1445",
+        rdfs:label "energy transformation function"
+    
+    SubClassOf: 
+        <http://purl.obolibrary.org/obo/BFO_0000034>,
+        OEO_00010121 some OEO_00000061
+    
+    
+Class: OEO_00010386
+
+    Annotations: 
+        <http://purl.obolibrary.org/obo/IAO_0000115> "An electricity generation function is an energy transformation function to transform other types of energy to electrical energy.",
+        <http://purl.obolibrary.org/obo/IAO_0000118> "electrical energy generation function",
+        <http://purl.obolibrary.org/obo/IAO_0000233> "issue: https://github.com/OpenEnergyPlatform/ontology/issues/1438
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1445",
+        rdfs:label "electricity generation function"@en
+    
+    SubClassOf: 
+        OEO_00010385
+    
+    
+Class: OEO_00010387
+
+    Annotations: 
+        <http://purl.obolibrary.org/obo/IAO_0000115> "A heat generation function is an energy transformation function to transform other types of energy to thermal energy.",
+        <http://purl.obolibrary.org/obo/IAO_0000118> "thermal energy transformation function",
+        <http://purl.obolibrary.org/obo/IAO_0000233> "issue: https://github.com/OpenEnergyPlatform/ontology/issues/1438
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1445",
+        rdfs:label "heat generation function"@en
+    
+    SubClassOf: 
+        OEO_00010385
+    
+    
+Class: OEO_00010388
+
+    Annotations: 
+        <http://purl.obolibrary.org/obo/IAO_0000115> "A renewable energy function is the energy transformation function to transform renewable energy.",
+        <http://purl.obolibrary.org/obo/IAO_0000233> "issue: https://github.com/OpenEnergyPlatform/ontology/issues/1438
+pull request: https://github.com/OpenEnergyPlatform/ontology/pull/1445",
+        rdfs:label "renewable energy transformation function"@en
+    
+    SubClassOf: 
+        OEO_00010385
+    
+    
 Class: OEO_00020001
 
     Annotations: 
diff --git a/src/ontology/oeo.omn b/src/ontology/oeo.omn
index ebb6a16df..61aef917f 100644
--- a/src/ontology/oeo.omn
+++ b/src/ontology/oeo.omn
@@ -186,6 +186,9 @@ Class: <http://purl.obolibrary.org/obo/BFO_0000030>
 Class: <http://purl.obolibrary.org/obo/BFO_0000031>
 
     
+Class: <http://purl.obolibrary.org/obo/BFO_0000034>
+
+    
 Class: <http://purl.obolibrary.org/obo/BFO_0000038>