Optimisation of hybrid micro-grid system for LTE base station

Abstract

This study explores the prospect of powering a Long-Term Evolution (LTE) base transceiver station (LTE BTS) with a Hybrid Renewable Energy System (HRES) in the rural areas of South Africa. The focus of the study is on harnessing the inherent advantage in HRES which in return reduces the Greenhouse Gas (GHG) emissions and operational costs associated with a Diesel Generator (DG) used to power LTE BTS in the rural areas. Moreover, the HRES will help with enhancing stability, reliability, and sustainability of electric power supply to fulfil the required LTE BTS loads. Hence, the proposed HRES consists of Photovoltaic (PV) system, Wind Turbine (WT), a Fuel Cell (FC), Hydrogen Tank (HT), electrolyser, converter, and a Battery Storage (BS) back-up. In addition, the Hybrid Optimisation of Multiple Energy Resources (HOMER) software coupled with Matrix Laboratory (MATLAB) software tool were selected for the simulation processes of the HRES. There are two sensitive variables that were inputted into the written codes and available HOMER tool. This was done in order to achieve an optimal result. The two sensitive variables are the PV tilt angle and the WT hub height. Hence, the effects of the PV tilt angle and WT hub height from the PV and WT systems have been infused into the system. By having knowledge of the load requirements of the selected LTE BTS site, two distinct configurations (PV/WT/FC/BS) and (DG/BS) simulation results have been compared, respectively. The simulation results clearly showed that in comparison to the DG/BS system, the proposed PV/WT/FC/BS HRES reduced the Net Present Cost (NPC), and GHG emissions by values of 40% and 100%, respectively. It was observed that the Capacity Shortage Fraction (CSF) was less than 1%, while the other important indicator such as the Renewable Fraction (RF) was increased by 100%. It is clear that the proposed HRES would improve the electric power supply to the LTE BTS at a reduced NPC and acceptable GHG emissions, which in-turn, alleviates excessive costs and environmental effects from GHG emissions.