Biodegradable waste quantities in Lithuania and their potential for the co-treatment in renewable energy and organic fertilizer production were investigated. Two scenarios were formulated to study the differences of the amounts of obtainable energy and fertilizers between different ways of utilization. In the first scenario, only digestion was used, and in the second scenario, materials other than straw were digested, and straw and the solid fraction of sewage sludge digestate were combusted. As a result, the amounts of heat and electricity, as well as the fertilizer amounts in the counties were obtained for both scenarios. Based on this study, the share of renewable energy in Lithuania could be doubled by the co-treatment of different biodegradable materials.