We solve the problem of environmentally friendly (i.e., energy-efficient) base station and relay-station planning for a simplified cooperative cellular network. We assume a two-hop transmission model based on the time-division multiplexing operation. We propose a twostep iterative algorithm where each iteration consists of an assignment step and a positioning step. We use the energy-normalized throughput as a greenness measure, defined as the ratio of the sum-rate to the total energy consumptions. Numerical evaluation is performed to find 1) the optimal positions of base-stations and relay-stations and 2) the optimal numbers of base-stations and relay-stations in terms of maximizing the energy-normalized throughput in a one-dimensional network.