TECHNO-ECONOMIC OPTIMISATION OF HYBRID SOLAR–BATTERY ENERGY SYSTEMS FOR SUSTAINABLE POWER SUPPLY IN PUBLIC TERTIARY INSTITUTIONS IN SOUTHWEST NIGERIA
Abstract
The persistent inadequacy and unreliability of electricity supply remain major constraints to
teaching, research, innovation, and institutional administration in public tertiary institutions across
Nigeria. Frequent grid interruptions have increased dependence on diesel-powered generators,
resulting in escalating operating costs, reduced energy security, and significant greenhouse gas
emissions. Although hybrid solar photovoltaic (PV)–battery energy systems offer a promising
pathway toward sustainable campus electrification, their successful deployment requires rigorous
techno-economic optimization to ensure long-term technical reliability, financial viability, and
environmental sustainability. This study develops a multi-objective techno-economic optimization
framework for hybrid solar PV–battery energy systems tailored to the electricity demand
characteristics of public tertiary institutions in Southwest Nigeria. An applied engineering research
design integrating campus energy audits, institutional load profiling, solar resource assessment,
hybrid system modelling, lifecycle cost analysis, and environmental impact assessment was
adopted. Hybrid system configurations comprising photovoltaic arrays, lithium-ion battery
storage, power inverters, grid connectivity, and diesel backup were optimized using renewable
energy simulation software to minimize Net Present Cost (NPC) and Levelized Cost of Electricity
(LCOE) while maximizing renewable energy penetration, supply reliability, and carbon emission
reduction. System performance was evaluated using key technical, economic, and environmental
indicators, including renewable energy fraction, annual operating cost, battery autonomy, excess
electricity generation, discounted payback period, internal rate of return, unmet electrical load, and
annual carbon dioxide (CO₂) emissions. Sensitivity analyses were further performed to examine
the influence of electricity demand growth, solar resource variability, battery replacement costs,
diesel fuel prices, and discount rates on long-term system performance. The optimization
framework demonstrates the potential of hybrid solar PV–battery systems to substantially improve
electricity reliability, reduce dependence on fossil-fuel generation, lower lifecycle energy costs,
and accelerate institutional decarbonization. The study provides a practical decision-support model
for university administrators, policymakers, energy planners, and development partners seeking to
implement economically viable and environmentally sustainable renewable energy systems within
higher education institutions.
