Assessing the techno-economics of modular hybrid solar thermal systems

Abstract

Abstract.A techno-economic assessment was performed on modular hybrid solar thermal (in particular, solar power tower) systems with combustion from natural gas as backup to provide a continuous supply of electricity. Two different configurations were compared, i.e. a Hybrid Solar Receiver Combustor (HSRC), in which the functions of a solar cavity receiver and a combustor are integrated into a single device, and a Solar Gas Hybrid (SGH), which is a reference hybrid solar thermal system with a standalone solar-only cavity receiver and a backup boiler. The techno-economic benefits were assessed by varying the size of the modular components, i.e. the heliostat field and the solar receivers. It was found that for modularization to be cost effective requires more than the increased learning from higher production of a larger number of smaller units, such as access to alternative, lower-cost manufacturing methods and/or the use of a low melting point Heat Transfer Fluid (HTF) such as sodium to reduce parasitic losses. In particular, for a plant with 30 units of 1MW th modules, the Levelized Cost of Electricity is competitive compared with a single unit of 30MW th after ~100 plants are installed for both the HSRC and SGH if the systems employ the use of sodium as the heat transfer fluid.

Performance characteristics of a hybrid solar receiver combustor utilising hydrogen or syngas

“…Despite its many potential benefits [7][8][9][10][11] , it has the disadvantage of a compromised receiver-combustor design to extract the heat efficiently from both a concentrated solar radiation (CSR) source and a combined radiation/convection source (combustion). Also, while the potential benefits of the device have been demonstrated by techno-economics analyses and recently by some experimental evidence [12][13][14][15][16][17][18][19] , only limited measurements of the performance of direct hybrids are presently available, with no data for systems fed with alternative, renewable fuels, so that a systematic investigation is needed to better evaluate the potential benefits with these fuels and assess the influence of the fuel composition on performance. This is critical, as the use of 'direct hybrids' with renewable fuels offers the additional potential for carbon-negative energy with relatively low-cost (while also increasing the amount of renewable in the system) 6 .…”