In this paper a DC power plant for base transceiver station power supply is investigated. The supply system employs clean alternative energy sources, namely photovoltaic (PV) modules, wind turbines, a fuel cell as backup generator and a storage battery bank. A detailed description is made and experimental data are shown of a prototype system where the PV modules are directly connected to the DC bus and an on/off strategy is used to control the power flow to the battery bank and to the load. The system is modeled and the model is validated comparing simulation results with experimental data. It is then investigated the possibility to add a DC-DC converter for optimized control of the energy generated by the PV strings. Simulation results show that the addition of a DC-DC converter between the PV modules and the DC bus brings a remarkable increase in the produced energy.