A hybrid system that uses photovoltaics (PV) and solar thermal energy separately to provide steam in the food and beverage industry is proposed and analyzed as a means to improve the sustainable of industrial process heating.

The system combines a solar thermal plant based on parabolic trough collectors (PTCs) connected to water storage and a PV facility coupled to a sand-based high-temperature heat storage system. The two facilities are planned to provide heat separately to the same industrial facility, with the PV unit being used when the solar thermal plant is unable to meet the heating demand.

Four different scenarios were simulated for an industrial site in southern Spain: a reference case where heat is provided exclusively by a conventional boiler; a system configuration based on the boiler and the solar thermal plant coupled to water storage; a hybrid system using the boiler and the PV plant linked to sand storage; and a system using both solar technologies connected to their respective storage systems.

The techno-economic analysis published in Energy Conversion and Management shows the system configuration using both solar technologies provides the lowest levelized cost of heat (LCOH) of €83.5 ($93.9)/MWh. The highest LCOH was associated with the system based on the conventional boiler alone at €100/MWh, while the system based on PV steam generation without solar thermal energy achieved an LCOH of €90/MWh. The system based on solar thermal energy without PV reached an LCOH of €84/MWh.

The PTC and PV systems complement each other to achieve superior economic and land area performance in addition to a very high combined solar fraction. The solar thermal unit can meet 30% of the industrial facility's heating demand, with the PV unit and the boiler covering 60% and 10%, respectively.

Researchers from Dalarna University (Sweden), Uppsala University (Sweden), Absolicon Solar Collectors AB (Sweden) and Polar Night Energy Oy (Finland) contributed to this study.