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the power consumption of wireless access networks has become a major economic and environmental issue. Providing dedicated low cost power supply to off-grid cell sites located in the rural and sub-urban areas of developing countries are most challenging, as most of the rural areas are not connected to the electricity grid and, even though they are connected, the availability of the supply is very limited to provide uninterrupted power supply. This paper proposes hybrid power systems (HPS) as alternative solution to the problems encountered with the offgrid cell sites. The paper further investigates the reliability figures and failure rate of the proposed hybrid power solution as compared with the conventional power system. The configuration of the HPS examined in this paper included a Solar Power System, Diesel generator and battery bank. Analysis of results shows that, after fifteen (15) years of operation, the reliability figures of both solar and hybrid power system are much higher than 80%. But that of the generator is already approaching 15%. Comparing these figures with the general bath tub, it can be seen that the reliability of generator after five years (ie 43800 hrs) of operation is already normal operation period and thereafter, the figure would degrade below 60% which would not be considered satisfactory operation. It was also found that, the proposed HPS system has very high reliability figures with a slight gain over the solar system and analysis of the mean time before failure (MBTF) shows that the, hybrid power system will work satisfactorily for twenty three (23) years before complete failure as compared with eight (8) years for …