Variability of Coal Quality in Tuzla Canton, Bosnia and Herzegovina: Implications for Energy Efficiency and Energy Transition

Abstract

Coal remains an important component of the electricity system of Bosnia and Herzegovina, while the country is simultaneously undergoing a gradual energy transition toward lower-carbon technologies. This study evaluates the quality of coal from major mining areas in Tuzla Canton using laboratory results for composite samples from Kreka, Đurđevik and Banovići. The principal indicators were total moisture, ash, combustible matter and lower heating value (LHV). Eight mining areas were compared using five analytical samples per area, giving 40 observations for the primary statistical analysis. An additional 15 observations from five Banovići separation products were evaluated separately. Marked differences were identified among mining areas. Mean LHV ranged from 7,836 kJ/kg at PK Dubrave to 19,794 kJ/kg at Jama Omazići. Lignite from the Kreka area had substantially higher mean total moisture than the analysed brown coals, while several brown-coal areas were constrained by high ash content. Across the 40 primary observations, LHV showed a moderate negative correlation with total moisture (r = -0.43) and with ash (r = -0.37). A multiple linear model using moisture and ash explained approximately 98.4% of the observed LHV variation, although the small number of samples and the compositional nature of the variables require cautious interpretation. The findings demonstrate that coal reserves alone are insufficient for evaluating the future role of coal: fuel quality, preparation efficiency, plant efficiency, emissions intensity, economic performance and regulatory conditions must be considered together. The results support a transition strategy that combines improved coal characterisation and combustion efficiency in the medium term with accelerated deployment of renewable generation, storage, grid modernisation and just-transition measures.