Hybrid Power System for Green Telecom Sites

Abstract: Solar Photovoltaic can offer a clean and cheap alternative to the Diesel Generator for telecom sites that are in remote locations with no grid coverage or where the grid is not fully reliable. Ericsson Enclosure & Power is looking into the opportunity to integrate this technology, together with battery storage, into their network sites around the globe, in view of a constantly growing network demand and the diffusion of the 5G technology. One of the main upfront cost is the civil works for the PV structure foundations and the company is interested in lighter weight PV chemistries, such as CIGS. Besides, they also noted how the thin-film technology harvest light in a different way than the standard crystalline silicon, which would represent an additional benefit of replacing c-Si with CIGS for certain locations. The aim of this thesis work is to investigate into the effect that a different radiation spectrum has for several PV chemistries, mainly c-Si and CIGS, to improve the Excel model, already started by the group, with more accurate information and algorithm for all the components of a hybrid diesel-solar-battery power system, to develop a dispatch strategy among the different sources and analyse the best mix that increases the share of renewables and gives the lowest payback period. It was found that, when the spectral effects are included in the model, there is no significant difference between c-Si and CIGS and their comparison can be done simply in terms of efficiency values, cost per unit of watt peak and weight-to-power ratio, for cheaper types of structures. Besides, the best mix is found for both a grid-connected and an off-grid sites, where a combination of PV, batteries and genset or grid is used. Utilizing renewable energy only, would require a significant oversizing of the system to cover the annual load, making the investment unattractive for the cost and the land needed. A pure solar system could represent an opportunity for sites that can accept planned shutdowns for a small fraction of the year.