Techno-Economic and Life-Cycle Impact Analysis of Solar Photovoltaic Microgrid Systems for Off-Grid Communities
Authors:   , Akinyele Daniel 
Published: November 2021

<p>This thesis proposes Solar Photovoltaic Microgrids (SPMs) for six different remote communities in Nigeria, one from each of the country’s geopolitical zones. The research analysis is presented based on the basic load demand of 24 households within each of the selected communities. The arrangements of the houses are obtained from the community’s layout provided by a building consortium.  The study first presents the intended users’ basic energy needs and their daily energy usage. The available solar energy resources of the different locations are also carefully examined, in relation to their disparities, intermittent characteristics and seasonal variations. The research also emphasises the possibility of load growth. With such consideration, more practical electrification solutions can be achieved. The study considers users’ electricity demand growth of 25 to 75% of the baseline value of 175 kWh/d.  The photovoltaic microgrid systems are modelled in the DIgSILENT PowerFactory environment. The lengths of the lines running from the electric power plant to the households are obtained from the community’s layout. This information is included in the model, coupled with the solar energy data and the technical configurations of the PV arrays.  The effectiveness of the proposed SPMs is evaluated by first comparing the techno-economic and environmental assessment results with those of a diesel power plant. This is also done by comparing the results with some existing related outputs in the literature, which are reported for solar photovoltaic systems in different regions of the world.  The research results indicate that it is possible to develop practical, cost-effective and reliable clean energy systems for the specified communities based on solar photovoltaic technology. The SPMs have the capability to compete with conventional electricity options – diesel/petrol generators with which some households are already familiar. Furthermore, even though the diesel plant’s initial capital cost is as low as ~ 10 - 17% of those of the SPMs, its life cycle costs are ~ 2 - 2.3 times the life cycle costs of the proposed SPMs for the six locations. Over the 25-year project life span, the SPMs clearly provide a significant economic benefit.  The battery average SoC probability distribution values of >98% above the minimum set point of 30% were also achieved. The reliability indices, i.e. LOEP of < 5%, availability of > 95% achieved in this study for the SPMs, are also comparable with the existing results in the literature. The SPM’s estimated emission rate is ~57 gCO₂/kWh, which is lower than the values of 576 - 695 gCO₂/kWh obtained for diesel systems. The SPM system’s GWP ranges from 3,409 to 7,945 kgCO₂-eq. Also, the system’s EPBTs and EROIs range from 1.11 to 1.6 years and 15.63 to 22.52, respectively, of the specified locations.  The proposed SPM model is based on the global engineering standards and best practices and has very considerable practical applications. These can provide a reference point for governments, policymakers, researchers, designers, planners, and other stakeholders of interest in conceptualising and proceeding with the design, planning, and development of new electrification systems for remote communities.</p>