A Feasibility Study of Solar and Wind Hybridization of a Telecommunication Off-Grid Radio Base Station Site

In order to expand cellular coverage and grow their market presence, mobile network operators in Kenya have had to deploy a significant part of their radio base station infrastructure in rural and remote areas, most of which are off-grid areas i.e., areas that are beyond the reach of the national electricity grid. The most common way to solve the power problem at these off-grid radio base stations has been to install and run diesel generator sets. Diesel generators have some inherent problems associated with them, which include; high cost of fuel, fuel delivery challenges, fuel pilferage, fuel supply disruptions, fuel price uncertainties, high generator maintenance costs, environmental pollution and system unreliability. Solar and wind are alternative sources of energy that can be used in standalone mode or in hybrid configuration to reduce reliance on diesel generators. The financial analysis and design of renewable energy systems can be challenging, due to the large number of design options and uncertainty in key parameters. Further complexity is added because their power output may be intermittent, seasonal, and non-dispatchable, and the availability may be uncertain. This case study was undertaken to determine the most feasible hybrid power solution for one off grid radio base station site belonging to a mobile network operator in Kenya through use of HOMER Microgrid analysis software tool. The load profile was measured using a digital power data logger and the maximum load estimated. Wind and Solar data was obtained from the National Aeronautical and Space Agency and National Renewable Energy Laboratory data bases respectively. Component costs, operational costs, diesel fuel prices and estimate interest rates were also obtained from both secondary and primary sources. Using this data, several hybrid system configurations were simulated and ranked according to the value of their Net Present Cost. The system with the lowest Net Present Cost is deemed as the most feasible configuration. Results from the study showed that the SolarDiesel Generator-Battery Bank configuration has the lowest Net Present Cost and would be the most feasible power solution for the study site.