Bioelectromethanogenesis, a technology to convert electrical energy into CH4, is on the transition from lab-scale to industrial application. But the question arises if it is really a sustainable technology or just another scientific artifact. Especially the energy efficiency is a crucial aspect to allow conclusions about the applicability. In this paper, the basics of energy calculations are applied to literature data to model the energy efficiency. Different scenarios were calculated, showing that further research has to be conducted to turn bioelectromethanogenesis into a feasible technology.