Abstract

Biogas from anaerobic digestion is a versatile energy carrier that can be upgraded to compressed biomethane gas (CBG) as a renewable and sustainable alternative to natural gas. Organic residues and energy crops are predicted to be major sources of bioenergy production in the future. Pre-treatment can reduce the recalcitrance of lignocellulosic energy crops such as Salix to anaerobic digestion, making it a potential biogas feedstock. This lignocellulosic material can be co-digested with animal manure, which has the complementary effect of increasing volumetric biogas yield. Salix varieties exhibit variations in yield, composition and biomethane potential values, which can have a significant effect on the overall biogas production system. This study assessed the impact of Salix varietal differences on the overall mass and energy balance of a co-digestion system using steam pre-treated Salix biomass and dairy manure (DaM) to produce CBG as the final product. Six commercial Salix varieties cultivated under unfertilised and fertilised conditions were compared. Energy and mass flows along this total process chain, comprising Salix cultivation, steam pre-treatment, biogas production and biogas upgrading to CBG, were evaluated. Two scenarios were considered: a base scenario without heat recovery and a scenario with heat recovery. The results showed that Salix variety had a significant effect on energy output-input ratio (R), with R values in the base scenario of 1.57-1.88 and in the heat recovery scenario of 2.36-2.94. In both scenarios, unfertilised var. Tordis was the best energy performer, while the fertilised var. Jorr was the worst. Based on this energy performance, Salix could be a feasible feedstock for co-digestion with DaM, although its R value was at the lower end of the range reported previously for energy crops.

Keywords

Salix; Energy analysis; Biogas; Lignocellulosic biomass; Short-rotation coppice willow; Systems perspective; Biomethane; Energy balance

Published in

Biotechnology for Biofuels and Bioproducts
2023, Volume: 16, number: 1, article number: 165
Publisher: BMC

SLU Authors

• Kalita, Saurav

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Ohlsson, Jonas

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Karlsson Potter, Hanna

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Nordberg, Åke

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Sandgren, Mats

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Hansson, Per-Anders

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure access to affordable, reliable, sustainable and modern energy for all


UKÄ Subject classification

Bioenergy


Publication identifier

DOI: https://doi.org/10.1186/s13068-023-02412-1

Permanent link to this page (URI)

https://res.slu.se/id/publ/126975