This study assesses the evolutionary trajectory of the knowledge base of Russian biofuel technology compared to that of Germany, one of the successful leaders in adopting renewable energy, and China, an aggressive latecomer at promoting renewable energy. A total of 1797 patents filed in Russia, 8282 in Germany and 20,549 in China were retrieved from the European Patent Office database through 2012. We identify four collectively representative measures of a knowledge base (size, growth, cumulativeness, and interdependence), which are observable from biofuel patent citations. Furthermore, we define the exploratory-exploitative index, which enables us to identify the nature of learning embedded in the knowledge base structure. Our citation network analysis of the biofiiel knowledge base trajectory by country, in conjunction with policy milestones, shows that Russia's biofuel knowledge base lacks both the increasing technological specialization of that in Germany and the accelerated growth rate of that in China. The German biofuel citation network shows a well-established knowledge base with increasing connectivity, while China's has grown exceptionally fast but with a sparseness of citations reflecting limited connections to preceding, foundational technologies. We conclude by addressing policy implications as well as limitations of the study and potential topics to explore in future research. (C) 2015 Elsevier Ltd. All rights reserved.