Analytical modelling for optimized selection between renewable energy systems and the conventional grid expansion

Abstract

The study aims to present the analysis of Economic Distance Limit (EDL) of conventional grid extension and some renewable energy systems for Gorkha District based on Life Cycle Cost (LCC) analysis. The study is an attempt to prepare a framework for the evaluation of a least cost electricity master plan which may be applied to other districts in future. An analytical tool has been followed to carry out the least cost electrification planning. The least cost planning has been done for the load forecast for the 5th year, which is 965 kW in aggregate. Accordingly, to meet this demand, it has been assumed that there will be 40 numbers of 25 kVA transformers feeding the settlements in the study Village Development Committee (VDCs), and an alternative option of electrifying these villages will consist of 40 Micro-Hydro Power plants (MHPs) of 25 kW capacities each. The result shows that extension from the existing grid points up to additional 22.41 km (economic distance limit, or EDL) is more economical than supplying through the installation of MHPs. A similar comparison was attempted with grid vs commercial scale solar photovoltaic (PV) for a theoretical load of 25 kW; the EDL for grid-extension has been worked out to be 47.96 km with battery storage. Furthermore, the costs of low voltage lines have not been included in comparison assuming they are common costs to both options. Reliability from the grid supply, MHPs and commercial solar PV has been assumed to be similar.