This paper explores the performance of public spending on the renewable energy sector. A panel Data Envelopment Analysis is employed to obtain efficiency scores. The case study is Italy and its 21 regions that implemented a Regional Energy Plan between 2003 and 2010. The findings show that special statute regions and Southern regions perform best in terms of technical efficiency under variable return to scale (VRS). On the whole, Italy shows an increase in the energy efficiency. Based on the Simar-Wilson bootstrap approach, a post-DEA is also run. These results provide evidence that being a southern region has a positive effect on the level of efficiency. Real GDP and the number of graduates in technical and scientific disciplines have a positive impact on the efficiency of the public intervention on renewable energy.