Technologies are generally described for reducing the from-power-grid energy consumption of a wireless network such as a cellular network over a period of time through cell size adaptations. According to some examples, cell sizes for the base stations may be optimized by decomposing the cell size optimization into two approaches: a multi-stage energy allocation approach and an energy consumption minimization approach. By implementing an energy allocation policy based on available energy type (e.g., from-power-grid or renewable) and an approximation technique for the energy consumption minimization, cell size optimization for each base station may be achieved resulting in network-wide enhancement of renewable energy usage vs. from-power-grid energy usage.