Sentence:  Gas injection through a porous anode ( transpiration cooling ) not only feeds back the <WSD>energy</WSD> transferred to the anode by the above mentioned processes , but also modifies the conditions in the arc itself . 
Meaning of the word marked with <WSD> tags:  (physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs