Feasibility Assessment of an Off-Grid Solar PV System with Battery Storage for an Academic Building: A Techno-Economic and Environmental Approach

Abstract

The rising cost of grid electricity and the instability of the national power network in Nigeria have made it necessary to find sustainable energy alternatives in academic institutions. This study evaluates the feasibility of integrating an Off-Grid solar photovoltaic (PV) power system with battery storage into a departmental building by conducting technical, economic, and environmental analyses using RETScreen Expert. The study provides a replicable framework for evaluating the feasibility of a solar PV system considering realistic electricity usage patterns and cost dynamics in Nigerian institutions. The analysis compared Grid electricity (Base case) with a photovoltaic PV solar (Proposed Case). RETScreen retrieved climate data such as daily solar radiation, cooling and heating degree-days, air temperature, and precipitation from ground-based weather stations and NASA satellites, which were used for analyses. Battery capacity and inverter size were calculated and selected to match the load; solar panel area was determined from the solar PV system. The capital and operating costs were used by the software to evaluate the annual cost savings, while financial parameters, including fuel cost escalation rate, inflation rate, discount rate and project life, were used by the software to assess Payback Period, Net Present Value (NPV) and Internal Rate of Return (IRR). Results from the analyses showed that the solar PV system is able to deliver 98.8% of the building’s load throughout the year and achieve a positive Net Present Value (NPV) over a 20-year project life with annual GHGs reduction of 7.3 tCO₂, which is 100% in reduction in GHG emissions. These results provide a data-driven framework for the department to optimise energy efficiency and reduce greenhouse gas emissions. Transitioning to solar energy can significantly mitigate the financial burden of rising electricity tariffs.