I know I should have used Forge Energy instead of RF, but because I am not sure how to implement Forge Energy, it is not in the mod yet.
Because of this, I am switching over to FE completely.
Feel free to pull request my repo for adding FE.

I am probably gonna keep RF support but adding FE at the same time for 1.10.2 and 1.11.2.
As for 1.12, Energy-based exchangers are not implemented yet so I will see when the supported mods are getting released.

You're actually good now on that for 1.10.2 (looking at your current repo), and I'm sorry - that was 100% on us and the API repo was just wrong.

For 1.12, the RF-API will be a 100% standalone jar. For an idea of how I set up Forge Energy support (it's trivial alongside RF), have a look here:

https://github.com/CoFH/CoFHLib/blob/master/src/main/java/cofh/lib/util/capabilities/EnergyContainerItemWrapper.java

Implemented here in the Cell:

https://github.com/CoFH/ThermalExpansion/blob/master/src/main/java/cofh/thermalexpansion/block/storage/ItemBlockCell.java