Board Thread:Questions and Answers/@comment-150.101.206.114-20130717034734/@comment-13413401-20140114005635

Thermal Expansion does not make a new form of energy. It uses Buildcraft energy (MJ). Its basically an addon for buildcraft to make it a lot better. Here are the types of energies in the game and the different mods that use it:

EU: Industrial Craft 2 Energy, used by MFR and Power Converters

MJ: Buildcraft Energy, used by MFR, Thermal Expansion, and Power Converters

Bluelectricity: Redpower Energy, not used by any other mods