Abstract: Energy and development are two things that are closely related; as energy availability increases, the rate of socio-economic development of a nation will equally increase and vice versa. The challenge in most developing nations of the world, including Nigeria, today is non-availability of appropriate electricity supply. In solving this problem, the use of generator sets has become the order of the day. Unfortunately, its uses rather than bringing the desired solution, has been a major source of environmental problem in recent times. To prevent this, a better alternate energy source that is cost effect and environmental hazard free must be encouraged worldwide. This study, therefore, takes a look at the environmental and cost effectiveness of using diesel generator set and solar as alternative energy sources using Nigerian Telecommunications (NITEL) Plc, as a case study. The study revealed the huge amount of Nitrogen Oxides (NO_x), Carbon (IV) Oxide (CO₂), Sulphur (IV) Oxide (SO₂) and particulates being emitted annually into the atmosphere by two repeater stations of this company alone. Also, through the cost comparative analysis carried out in this study, it was found that over 40% of the company`s expenditure on diesel and maintenance of the generator would have been saved if solar was being used. Hence, the study established the fact that the use of solar is more economical and environmentally safer than generator set. The paper concludes with suggestion on how to encourage world energy-environmental friendly policy as well as how to avert the adverse effects of total exhaustion of non-renewable energy for socio-economic development.