Techno-Economic Assessment of a Grid-Interconnected Parabolic Trough Collector System in Garissa County, Kenya: A Comparative Study with an Existing Solar Photovoltaic Plant

This study, conducted and finalized in early 2026, presents a comprehensive techno-economic assessment of a proposed 50.4 MW grid-interconnected parabolic trough collector (PTC) concentrating solar power (CSP) plant in Garissa County, north-eastern Kenya, benchmarked against the operational 54.6 MW Garissa Solar Photovoltaic (PV) Plant, in response to Kenya's expanding energy demand and commitment to renewable energy targets across its diverse climatic zones. Technical performance analysis of the existing PV plant utilized historical operational data covering the full 2024 calendar year (January–December 2024), analyzed retrospectively in accordance with IEC 61724-1:2021. The proposed CSP plant was simulated using the System Advisor Model (SAM, version 2025.4.16), employing validated Direct Normal Irradiance (DNI) data from the National Solar Radiation Database (NSRDB version 4) corresponding to the same 2024 reference year, ensuring direct comparability between the historical PV dataset and the simulated CSP output. Results show that the PV plant generated 82,457.59 MWh annually with a Capacity Utilization Factor (CUF) of 17.22% and a Performance Ratio (PR) of 66.71%. The simulated CSP plant, equipped with 8 hours of thermal energy storage, achieved annual net generation of 169,601.94 MWh, a CUF of 38.4%, and a specific yield of 3,365 kWh/kW/year, 2.23 times the PV plant value. Both technologies converged on comparable Levelized Cost of Electricity (LCOE) values of approximately 7.3 USD cents/kWh over a 25-year lifetime. Under the prevailing Power Purchase Agreement (PPA) tariff of 5.49 USD cents/kWh, which is approximately 24.79% below the calculated LCOE, both plants exhibit negative financial viability metrics, underscoring the critical role of sovereign guarantees and tariff reform. Greenhouse gas assessments reveal that the CSP plant could displace 9,823 tCO2eq annually versus 4,776 tCO2eq for the PV plant. These findings reinforce the strategic value of concentrated solar power (CSP) with thermal energy storage as a source of dispatchable clean electricity in semi-arid, high-direct-normal-irradiance (DNI) regions. At the same time, they underscore the need for policy-supported revenue mechanisms to enhance investment certainty and attract private capital.