This paper aims to examine whether public policy has played a significant role in fostering innovation in renewable energy technologies within OECD countries. The analysis covers a 26 year time period (1978-2003) and uses variable patent activity as a proxy for technological innovation, examining the role of public policy instruments on this issue. The study assesses the effect of numerous policy variants, for instance:

price supports
tax credits
voluntary programmes
tariffs.

Obligations on patent activity are also examined in the spheres of:

solar energy
wind energy
bio-energy
ocean
geothermal energy.

The data analysis indicates a sharp rise in patent activity related to wind and waste-to-energy since the mid-1990s and continuing innovation in the field of solar energy. Innovation efforts using biomass, geothermal and ocean energy however, are found to be low. The study asserts that public policy specifically does play a key role in prompting an increase in patent activity in renewable energy technologies which can be equated to innovation in this sphere. The study reveals taxes, obligations, and tradable certificates as the most significant policy instruments, while noting that the efficacy of policy instruments differs for different renewable energy sources.