This paper addresses the energy-conserving routing problem in wireless ad-hoc networks, where nodes have limited initial energy and must forward information to designated gateway nodes. The authors propose algorithms to select routes and power levels that maximize the system lifetime, which is defined as the time until the first node's battery drains out. The algorithms are local and distributed, and they are shown to converge to optimal solutions when there is a single power level. For multiple power levels, the achievable lifetime is close to the optimal value computed by linear programming. The key insight is that to maximize the lifetime, traffic should be routed such that energy consumption is balanced among nodes in proportion to their energy reserves, rather than minimizing the absolute consumed power. The paper includes a detailed formulation of the problem, a class of flow augmentation algorithms, and a flow redirection algorithm, along with simulations that demonstrate the effectiveness of the proposed algorithms in improving the system lifetime compared to conventional minimum transmitted energy routing.This paper addresses the energy-conserving routing problem in wireless ad-hoc networks, where nodes have limited initial energy and must forward information to designated gateway nodes. The authors propose algorithms to select routes and power levels that maximize the system lifetime, which is defined as the time until the first node's battery drains out. The algorithms are local and distributed, and they are shown to converge to optimal solutions when there is a single power level. For multiple power levels, the achievable lifetime is close to the optimal value computed by linear programming. The key insight is that to maximize the lifetime, traffic should be routed such that energy consumption is balanced among nodes in proportion to their energy reserves, rather than minimizing the absolute consumed power. The paper includes a detailed formulation of the problem, a class of flow augmentation algorithms, and a flow redirection algorithm, along with simulations that demonstrate the effectiveness of the proposed algorithms in improving the system lifetime compared to conventional minimum transmitted energy routing.