Abstract— We investigate the energy-saving potential of transport protocols. We seek an answer to strategic issues of maximizing energy and bandwidth exploitation, without damaging the dynamics of multiple-flow equilibrium. We claim that (i) an energy-saving strategy of the transport level needs to be associated with some energy potential index which, unlike energy expenditure, is not device-specific and (ii) system-wise an energyefficient system of flows is not always a better choice: we show that a less energy-efficient system may be more reliable in terms of packet multiplexing and, in turn, may reduce the probability that some flows may expend their energy with zero gain. We present results using a real testbed.