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

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.