This paper analyzes dynamic economies in renewable energy technologies. The paper has two contributions. The first is to test the robustness of experience in solar photovoltaic, solar thermal and wind energy to the addition of an explicit time trend, which has been done in experience studies for other industries, but not for renewable energy technologies. Estimation is carried out on the assumption that cumulative capacity, industry production, average firm production, and electricity generation affect experience and thus the fall in price. The second contribution is to test the impact of R&D on price reduction. In general cumulative experience is found to be highly statistically significant when estimated alone, and highly statistically insignificant when time is added to the model. The effect of R&D is small and statistically significant in solar photovoltaic technology and statistically insignificant in solar thermal and wind technologies. (c) 2004 Elsevier Ltd. All rights reserved.