Assessment of the energy potential of unused biomass in Bulgaria with emphasis on the Northeastern region

Technical university of Varna, Department of Thermal engineering, 9010 Varna, Bulgaria

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study explores the availability of biomass in Bulgaria, with a focus on the portion that remains unused and its potential for energy production. The analysis is based on statistical data covering the main sources of biomass, including agricultural, forest, and agro-industrial residues, and applies commonly used assessment approaches such as residue-to-product ratios, utilization factors, and lower heating value calculations to estimate the available energy potential. The results show that Bulgaria has a total biomass potential of about 17.5 Mt/year, of which approximately 35–45% is not utilized, equal to around 6.0–7.0 Mt/year. The largest share of this unused resource comes from agricultural residues. In energy terms, this corresponds to an estimated potential of about 26 TWh/year, which could contribute significantly to the country’s energy demand. Particular attention is given to the Northeastern region of Bulgaria, where biomass resources are highly concentrated and largely underutilized. The study also discusses the main challenges limiting biomass use, such as logistical difficulties, economic constraints, and technological limitations. Overall, the findings highlight the need for better infrastructure, wider adoption of modern technologies, and supportive policies to unlock the full potential of biomass as a sustainable energy source.