Parametric study of the techno-economic performance of Solar-MGT systems

Solar-assisted micro gas turbine (Solar-MGT) systems offer a promising solution for decentralised power generation by combining the reliability of gas turbines with the fuel-saving benefits of solar thermal input. This study presents a comprehensive techno-economic assessment of a Solar-MGT configuration using a detailed off-design model validated against both laboratory microturbine experiments and solar-assisted operation. A full-year simulation based on real meteorological data for Pretoria, South Africa captures the coupled effects of ambient conditions, receiver behaviour, Thermal Energy Storage (TES) operation, and component off-design performance within a unified framework. A refined component-level cost model is integrated into the analysis, enabling the influence of key subsystem characteristics on overall economic performance to be quantified. An extensive parametric study evaluates the impact of turbine inlet temperature, dish area, TES mass and charging temperature, recuperator effectiveness, and system mass flow rate. When parameter variations are normalised to represent similar increases in capital expenditure, the resulting designs span fuel-to-electric efficiencies of about 14–30% and levelised costs of electricity in the range 0.4–0.8 €/kWh. Upgrades focused on turbomachinery efficiency or recuperator effectiveness deliver the lowest costs of electricity (down to ≈0.4–0.76 €/kWh), albeit with a modest reduction in solar share, whereas increases in dish area or operating temperature mainly raise the solar contribution with more limited economic benefit. The findings demonstrate that optimal Solar-MGT performance arises from balanced combinations of design parameters rather than extreme values. The results highlight the importance of integrated, year-round techno-economic modelling for identifying realistic design pathways and guiding future Solar-MGT deployment.