Techno-economic assessment of Grid-tie Solar PV system in Kenya

Abstract

An increase in the cost of electricity in Kenya is partly due to the significant reliance on fossils fuels, which are unsustainable as well as environmentally unfriendly. In the electricity generation mix of 2854 MW in 2021, 26% was obtained from thermal (fuel) while solar contributed 2%. The adverse effects related to fossil fuel have resulted in the government and private investors exploring the abundant renewable energy source (solar) as an alternative, although at a slower pace. The purpose of this study was to increase the uptake of solar Photovoltaic (PV) technology in Kenya by providing crucial information to be considered by investors in solar PV technology. The main objective of the study was to fill the knowledge and contextual gap on the technical and economic analysis of the performance of the grid-tie solar (PV) systems in Kenya. Specific objectives were to evaluate and compare the monthly performance of simulated and measured energy generation of the PV system; to determine the performance of the technical and economic parameters of the case study PV system and compare to other design models and finally to analyse the benefits of the saved amount of carbon emission. The study evaluated a 54kWp system consisting of 216 solar PV modules, three(25kW) grid-tie inverters, nine (8kW) islanding inverters, and battery backup, installed on the rooftop of ‘Daima Towers’ in Eldoret, Kenya (0.516° N and 35.282° E). The system was monitored for one year in 2020. Primary data was collected by observation, survey, and inspection of the system as well as face-to-face interviews with the system engineer. Secondary data was obtained from the building’s financial records and Kenya power (KPLC) electricity billing records. Simulation software (PVsyst 6.86) was used to analyse the input data that included component specification, Investments made, operation conditions, and meteorological site data. Meteorological site data were v imported from the NASA-SSE database (1983-2005) using geographical coordinates input into the PVsyst meteorological data management platform. The measured yearly energy was 82 MWh compared to simulated energy of 87 MWh, an average difference of 6%, the high consistency reported verified that simulation results were reliable. The final yield (FY) was 1518 kWh/kWp and reference yield (RY) was 1943 kWh/kWp. Capacity utilization factor (CUF), performance ratio (PR) and PV penetration levels (PL) were 0.173, 0.78 and 0.170 respectively. Levelised cost of energy (LCOE) from solar was kshs. 12 / kWh compared to kshs. 22 / kWh on the grid imports. The system had return on investment (ROI)) of 103% with a simple payback period (S.P.B.P) of 12 years. Comparison to other possible design model shows that design with no battery storage would give the highest technical and economic performance. The saved carbon emission was 677 tons in the PV system lifetime which is equivalent to planting 564 mature trees. These analysis shows that the technical, economic and environmental benefits of grid-tie solar PV technology are worth the investment. The study recommends the use of real time and accurate meteorological instruments and sub energy meters to improve on accuracy of these results.