The paper presents the results of pyrolysis process applied as pre-treatment sequence for grape marc within energy conversion chain. Experimental campaign for proximate, ultimate and calorimetric characterization of the product was conducted. The product equivalent chemical formula was established -C4H7O3. The atmospheric pressure pyrolysis with external heat source at temperatures between 350 degrees C -600 degrees C was studied with respect to process parameters influence on end-products formation, distribution and physical-chemical properties. Based on experiments the product activation energy of 111.5 kJ/mol was determined. The process parameters influence on end-products energy content, pyrolysis energy consumption and global energy efficiency was established. The research focused on maximum net energy content delivered in pyrolysis products as high quality fuel for energy conversion processes. The study revealed that pyrolysis gas alone can ensure the process self-sustenance for the applied temperature range. The optimum treatment temperature with respect to global energy balance was found at 550 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.