Exploring the techno-economic feasibility of new bioeconomy concepts: Solar-assisted thermochemical biorefineries

Abstract

Integrating thermochemical biomass conversion and solar thermal energy is an emerging concept for the sustainable production of electricity, biofuels, and other renewable products. This study uses a utility supply approach to assess the techno-economic feasibility of thermochemical biorefineries (TBRF) assisted by concentrated solar power (CSP) systems. Three TBRF scenarios were modelled to produce dimethyl ether (DME) from gasified biomass (500 MWth), considering different alternatives for syngas upgrading. A CSP plant of 50 MWe and 15 h of thermal energy storage (TES) was incorporated to increase the system power generation. The assessment of the six scenarios (3 stand-alone and 3 CSP-assisted) was based on a specific location to show its potential: the solar resource of Seville (Spain) and the electricity prices in the Iberian market, both at hourly resolution. The CSP-assisted scenarios show fuel upgrading in the range of 2–4%, up to 85% of electricity demand coverage and power surpluses of up to 52% of its annual demand. However, the inclusion of a CSP block leads to an increase in investment costs of up to 74% and a decrease in the internal rate of return (IRR) of 9.2 points compared to a stand-alone TRBF. The DME minimum selling price ranged from 14 to 18.1 USD/GJ for the stand-alone scenarios and between 18.3 and 21.2 USD/GJ for the CSP-assisted scenarios. Furthermore, these results suggest that modular integration based on commercially available technologies may constitute a first step towards the feasibility of future biorefineries.