In ad hoc mobile wireless networks, energy consumption is an important issue as most mobile hosts operate on limited battery resources. Existing models for evaluating the energy consumption behavior of a mobile ad hoc network have shown that the various components of energy related costs include transmission power as well as the power of reception. In this paper, we extend the model for calculating the energy spent at a node due to a flow in the network. We include the transmission and reception costs if the node belongs to a flow, and reception costs if it is near a flow. This model gives the energy costs of nodes in ideal conditions where interference is absent, and hence can be extended to evaluate the effect of interference between flows on energy consumption in more realistic conditions. The collisions due to the flows are also measured, which are used to evaluate the effect of such interference in the energy consumption. We then show how the extra energy spent due to colli...