A Hybrid wind-solar energy-based electric power supply for a base transceiver station

Abstract

Due to the increasing number of mobile users, there is huge demand for Base Transceiver Stations (BTSs) particularly in rural and semi-urban areas. Currently in Ghana, BTSs are operated on diesel electric generators which cause a lot of noise and give carbon dioxide emissions. In this research, a hybrid wind-solar system with battery back-up is proposed to fulfill the power requirements of a BTS and associated loads. Field and feasibility studies conducted at a Kintampo BTS site (Latitude: 8° 03' 22.57" N and Longitude: -1° 43' 50.09" W) indicate that powering the BTS load from the proposed system as the wind speed varies from 4.49 m/s to 6.28 m/s and solar irradiance varies from 3.9 kWh/m2/day to 6.36 kWh/m2/day is technically and economically feasible. Based on design concept and criteria and selection of components, proposed system was modelled, and simulated for components validation and optimisation using HOMER software. Contributions of wind and solar PV to total annual energy production stood at 14% and 86%, respectively. Based on sensitivity analysis conducted, the proposed system stands to be viable except at a wind speed of 3 m/s. At a fixed solar irradiance of 5.22 kWh/m2/day, fixed wind speed of 5.43 m/s, fixed interest rate of 6.3% and 20% reduction in capital costs of both wind turbine and solar PV, cost of energy for the new system stood at USD 0.217 per kWh. The proposed system offers a reduced cost of energy of USD 0.249 per kWh as compared to 0.320 per kWh for the existing diesel electric generator-based system using the same parameters. The proposed system is 2.8 times cheaper than the existing system in terms of net present cost and it does not give CO2 emissions into the atmosphere due to 100% renewable fraction.