docs: restore sci guide terms for calc

Signed-off-by: Joseph Cook <[email protected]>

docs/implementations/sci-o.md

@@ -6,6 +6,14 @@ Operational emissions refer to the carbon generated by a component while it is i
 
 To calculate the operational emissions `o` for a software application, use the following:
 
+```
+O = E * I
+```
+
+where `O` = operational emissions, `E` = energy in kWh, and `I `= grid carbon intensity. 
+
+In the IEF implementation the calculation is expressed using the following terms:
+
 ```
 o = (energy * grid-ci)
 ```