diff --git a/TODO.md b/TODO.md
index 7ab8e26..120fe8b 100644
--- a/TODO.md
+++ b/TODO.md
@@ -61,6 +61,7 @@
 
 ## Units
  - long prefixes (megatonne, etc)
+ - Unit order h\*kW vs kW\*h
  - Print units with powers instead of /
  - HMS for degrees
  - Exact radians, using pi constant?
diff --git a/buildscript/constants.toml b/buildscript/constants.toml
index 3bfa992..6a1e1e6 100644
--- a/buildscript/constants.toml
+++ b/buildscript/constants.toml
@@ -73,4 +73,34 @@ unit = true
 enum_name = "PPQ"
 strings = "ppq"
 value = "1e-15"
+unit = true
+
+[[constant]]
+enum_name = "KWH"
+strings = "kWh"
+value = "kW * hour"
+unit = true
+
+[[constant]]
+enum_name = "MWH"
+strings = "WMh"
+value = "MW * hour"
+unit = true
+
+[[constant]]
+enum_name = "GWH"
+strings = "GWh"
+value = "GW * hour"
+unit = true
+
+[[constant]]
+enum_name = "TWH"
+strings = "TWh"
+value = "TW * hour"
+unit = true
+
+[[constant]]
+enum_name = "PWH"
+strings = "PWh"
+value = "PW * hour"
 unit = true
\ No newline at end of file