Open Access

REVIEW

Synergistic Integration of Hybrid Renewable Energy Systems for Energy-Autonomous Biorefineries: A State-of-the-Art Review

Adnan Asad Karim^1,2,*, Roque Aguado Molina³, Marcos Tostado-Véliz⁴, Paúl Arévalo-Cordero⁵, Emmanuel Ayorinde Ajiboye⁶
1 Department of Chemical, Environmental and Materials Engineering, Linares Scientific and Technological Campus, University of Jaén, Avda. de la Universidad s/n, Linares, Spain
2 University Institute of Research on Olive Groves and Olive Oil (INUO), GEOLIT Science and Technology Park, University of Jaén, Mengíbar, Spain
3 Institute of Carbon Science and Technology, Spanish National Research Council (CSIC), Oviedo, Spain
4 Department of Electrical Engineering, Linares Scientific and Technological Campus, University of Jaén, Avda. de la Universidad s/n, Linares, Spain
5 Department of Electrical Engineering, Electronics and Telecommunications (DEET), Faculty of Engineering, University of Cuenca, Balzay Campus, Cuenca, Ecuador
6 Centre for Critical Minerals, College of Earth and Minerals Science, Pennsylvania State University, State College, PA, USA
* Corresponding Author: Adnan Asad Karim. Email:
(This article belongs to the Special Issue: Next-Generation Bioenergy Systems for a Carbon-Neutral Future: Process Intensification, Hybrid Integration, and Scale-Up)

Energy Engineering https://doi.org/10.32604/ee.2026.084829

Received 29 April 2026; Accepted 08 July 2026; Published online 31 July 2026

Abstract

Biorefineries are an important pathway for the sustainable valorization of biomass, especially in rural and resource-distributed regions. However, their economic and environmental performance depends strongly on how energy is supplied to the biorefineries. The use of fossil-based heat and power can reduce their overall sustainability. Integrating renewable energy systems offers a promising alternative. This review examines the technical aspects of the integration of hybrid renewable energy systems (HRES) into biorefineries to achieve energy autonomy. Quantitative analysis identifies thermal operations like drying (6–15 MJ kg⁻¹) and distillation (8–14 MJ kg⁻¹) as primary energy sinks, while biochemical processes like fermentation require only 0.8–2.0 MJ kg⁻¹. Integrating concentrated solar thermal systems can achieve solar-to-syngas efficiencies of 20%–35% and reduce internal biomass consumption as a heat source by 33%. The study highlights that solar-assisted systems can increase overall energy efficiency to 54%–75%, significantly higher than the 34% seen in standalone plants. Additionally, wind energy-integrated facilities can reduce greenhouse gas emissions by 92.5%, and advanced solid oxide fuel cell hybrids demonstrate electrical efficiencies up to 63%. Biomass-powered combined heat and power systems integrated with district heating can achieve 70%–90% overall efficiency. However, economic barriers exist, such as a 74% increase in capital costs for certain solar-assisted configurations. The review concludes that decentralized, HRES-powered biorefineries offer a sustainable pathway for regional energy security by overcoming intermittency through synergistic technology integration.

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Keywords

Biomass conversion; biorefinery; renewable energy; de-fossilization; circular bioeconomy

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