The increasing deployment of cellular networks across the globe has brought two issues to the forefront: the energy cost of running these networks and the associated environmental impact. Also, most of the recent growth in cellular networks has been in developing countries, where the unavailability of reliable electricity grids forces operators to use sources like diesel generators for power, which not only increases operating costs but also contributes to pollution. Cellular base stations powered by renewable energy sources such as solar power have emerged as one of the promising solutions to these issues. This article presents an overview of the state-of- the-art in the design and deployment of solar powered cellular base stations. The article also discusses current challenges in the deployment and operation of such base stations and some of the proposed solutions.