Pyrolyzed Agro-Food By-Products: A Sustainable Alternative to Coal

Area of Science:

• Sustainable Energy
• Biomass Pyrolysis
• Circular Economy

Background:

• European energy systems heavily rely on fossil fuels, contributing to significant carbon emissions.
• There is a growing need for sustainable alternatives to coal to reduce dependence on fossil fuels and mitigate climate change.
• Agricultural and forestry residues represent underutilized biomass resources with potential for energy generation.

Purpose of the Study:

• To investigate the potential of biochar derived from various residues (spruce wood, spent coffee grounds, tea waste, nutshells) as a sustainable substitute for coal.
• To evaluate the energy properties and economic viability of pyrolyzed biomass for European energy applications.
• To assess the contribution of biomass pyrolysis to decarbonization and the advancement of a circular economy.

Main Methods:

• Biomass residues were subjected to pyrolysis at temperatures ranging from 250-550 °C.
• The calorific value, elemental composition, energy retention, and mass loss of the resulting biochar were analyzed.
• An economic analysis was performed to compare the cost-effectiveness of biochar against coal, considering emission allowance costs.

Main Results:

• Pyrolysis significantly improved the energy density of the biomass residues, with optimal temperatures varying by material.
• Spruce wood reached 31.56 MJ·kg⁻¹ at 550 °C (21.84% mass retention), while spent coffee grounds peaked at 31.26 MJ·kg⁻¹ at 350 °C (37.53% mass retention).
• Economic analysis indicated that pyrolyzed biomass is a cost-effective alternative to coal, particularly when accounting for emission costs.

Conclusions:

• Biochar derived from sustainable biomass residues is a viable and cost-effective substitute for coal in European energy systems.
• Integrating biomass pyrolysis supports regional decarbonization efforts, reduces greenhouse gas emissions, and promotes a circular economy.
• This approach decreases reliance on fossil fuels and enhances energy security.