This paper studies the knowledge spillovers generated by renewable energy technologies, unraveling the technological fields that benefit from knowledge developed in storage, solar, wind, marine, hydropower, geothermal, waste and biomass energy technologies. Using citation data of patents in renewable technologies filed at 18 European patent offices over the 1978–2006 period, the analysis examines the importance of knowledge flows within the same specific technological field (intra-technology spillovers), to other technologies in the field of power-generation (inter-technology spillovers), and to technologies unrelated to power-generation (external-technology spillovers). The results show significant differences across various technologies. Overall, patents in wind, storage and solar technologies tend to be more frequently cited than other technologies. While wind technologies mainly find applications within their own field, a large share of innovations in solar energy and storage technologies find applications outside the field of power generation. The paper discusses the implications of these results for policymaking.