This paper investigates whether a convergence or divergence of national innovation capabilities regarding renewable energy patents of the 13 EU countries occurs in the course of the time period 1990-2010. An answer to the research question permits immediate conclusions with regard to the success prospects of the EU's Renewable Energy Directive (2009/28/EC), which sets climate and energy targets for both 2020. The empirical analysis is focused on whether renewable energy patents have converged or diverged between the countries. The data is based on patents granted at the European patent office. The methodologies applied draws from the economic convergence literature. The initial results have showed signs of conditional beta and sigma divergence in renewable energy invention abilities.