The use of concentrated solar thermal (CST) to drive endothermic processes, such as supercritical water gasification (SCWG) is an attractive option for green fuel production, and has been demonstrated at laboratory scale. However, there is a lack of understanding of the system-level challenges and economic feasibility of such a technological route. As such, this work is focused on the techno-economic analysis of algae-to-liquid fuel production via solar-driven SCWG-reforming and Fischer Tropsch (FT) processes. A detailed steady-state physical model of the plant is developed in Aspen Plus software. Algae slurry, with 15.2 wt.% concentration of biomass, is considered as the feedstock. The total solar-thermal power delivered to the on-sun gasification and reforming reactors is assumed to be 50 MWth. There is an on-site syngas storage acting as a buffer between the intermittent SCWG-reforming and continuous FT units. The heat exchanger network is optimised for maximum syngas production, and thus liquid fuels including gasoline and diesel. The techno-economic evaluation of the system is carried out for an nth plant design for commercial units considering a plant lifetime of 30 years. The total cost of the plant includes capital investment, (fixed and variable) operating costs as well as a penalty cost for CO2 emissions. With 2016 as the basis year for costing, the proposed system has a levelised cost of fuel (LCOF) as low as 3.2 AUD/L (2.44 USD/L) of gasoline equivalent (at a solar multiple of 3.5 and 15 h syngas storage capacity) with the total capital investment of similar to 160 million AUD, producing 7600 tonnes of fuel per year ( 145 bbl/day) and achieving a capacity factor (CF) of similar to 70%. The sensitivity analysis of economic variables indicates that the feedstock cost, here algae, is the most influential factor, followed by the discount rate, and the capital costs of the FT, the syngas storage and the receiver unit. Although the estimated LCOF in this study seems to be relatively high compared to fossil fuel-based petroleum products, this technology has the prospect of becoming economically competitive in the near future based on the anticipated decrease in the cost of large-scale algae production and CST/FT plant scale-up.