Comparison of Parabolic Troughs and Solar Photovoltaic as Solar Field Technology in Dispatchable Solar Power Plants

Abstract

The use of thermal energy storage (TES) technologies, as means to provide dispatchability to thermally driven solar power production, has long stood as the main argument for the interest and potential competitiveness of Concentrated Solar Power (CSP) when compared to other non-dispatchable alternatives. Whereas reductions of the Levelized Cost of Electricity (LCOE) are observed for CSP in recent years, the notable LCOE reduction observed along this decade in large-scale solar photovoltaics (PV) plants is set to break the taboo of "power-to-heat-to-power" approaches, as its potential economic performance outcasts the associated thermodynamic inefficiency. The possibility of using available resistive heating technologies and components in PV-TES combinations, renders the configuration of a conventional CSP plant suitable for the replacement of a thermal conversion solar field by a photovoltaic field presenting further the possibility of delocalization and/or spatial distribution of the solar field (e.g. on a Carnot Battery configuration). As dispatchability no longer stands as an exclusive argument in favor of CSP over PV, the present article addresses the boundary conditions for the competitiveness of each technology as the champion of dispatchable solar power fields. The impact of both land and electrical heater costs variation in the variation of LCOE for PV-TES plants is much more modest than that observed for the impact of CSP solar field cost variations in the variation of LCOE for CSP plants, which leans for the latter and at present costs, towards better competitiveness for plant designs with a storage capacity in excess of 10.0 FLH (for GHI values in excess of 2100-2200 kWh∙m-2∙year-1).