Feasibility Study of an Off-grid PV/Wind/Generator Hybrid System for Remote Mobile Base Station (Case Study: Hadnet Mobile Base Station)
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Date
2019-07
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Addis Ababa University
Abstract
There is a clear challenge to provide reliable cellular mobile service at remote locations where a
reliable power supply is not available. So, the existing mobile towers or base transceiver station
(BTSs) use a conventional diesel generator with backup battery banks. However, the current
increase in diesel price and the negative effects of fossil fuels on the environment motivates to
search for other alternative (preferably renewable) sources of energy. In this work, feasibility of
PV/Wind/Generator hybrid system with battery storage as a backup is studied to provide a
reliable electric power for a specific remote mobile base station located at Hadnet, Wukro,
Tigray. The feasibility of this study is analyzed using HOMER (Hybrid Optimization Model for
Electrical Renewable) software. The study utilized meteorological data obtained from National
Meteorological Service Agency of Ethiopia and NASA to estimate the solar and wind energy
potentials. The load consumption data for the base station is collected from network and
operation center section of Ethio-telecom organization.
The best optimal system configurations namely PV/Wind/Generator/Battery and PV/Wind
/Battery hybrid systems are compared with the conventional stand-alone diesel generator (DG)
system. Findings indicated that PV/Wind/Generator/Battery hybrid system is the most
economically viable option with a total cost of $168,137 for the whole system project life time,
i.e. 20 years and for the diesel generator system the total cost is $653,602 for the whole system
project life time. And the levelized cost of energy (COE) for both systems is $0.282/kWh and
$0.729/kWh respectively. This implies the hybrid system saves $485,465 in terms of NPC and
$0.447/kWh in terms of COE to the network operator. Also, simulation results show that the
renewable energy source based hybrid energy system can decrease amount of air pollutants as
compared to the conventional diesel generator only and so a reduction of 38,657kg/yr of CO2,
95.38 kg/yr of CO, 10.532 kg/yr of UHC, 7.192 kg/yr of PM, 77.66 kg/yr of SO2, and 851.3
kg/yr of NOx is observed and saves about 14,680 liters of fuel per annum to the network
operator. The sensitivity analysis is also carried out to analyze the effects of probable variation in
solar radiation, wind speed, diesel price and average annual energy usage of the system load in
the optimal system configurations. As a result, this study has verified that the hybrid system is superior to the diesel-only system for
power generation at the BTS site from the perspective of economic, reliability and environmental
analysis.
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Keywords
Base Transceiver Station (BTSs), Hybrid system, Photovoltaic (PV), wind, Generator, HOMER