Production, consumption and research on solar energy: The Spanish and German case

• Growth in solar energy production and demand in Spain and Germany is exponential while linear in research production.
• Scientific output of Spain and Germany represents 51% of all publications on solar energy from EU.
• Universities are most productive bodies in both countries; companies have low representation.
• International collaboration ratios of Spain and Germany are higher than world and USA average.

An analysis of scientific publications on solar energy was conducted to determine whether public interest in the subject is mirrored by more intense research in the area. To this end, the research published by Spain and Germany, the two EU countries with the highest installed photovoltaic capacity, was analyzed based on Web of Science data. The results show that: solar output has risen substantially; solar research has a greater impact (measured in terms of citations) than publications on other renewables such as wind power; scientific production on solar energy is high in Germany and Spain, which together account for 51% of the total in the EU-27; the pattern of topics researched in the two countries is very similar; and their international collaboration is more intense than the world average and higher than in countries such as the USA, China or Japan. Collaboration between them is likewise intense. The main conclusion is the divergence in Germany and Spain between solar energy demand/output growth, being exponential, and the growth of research papers on the subject, which is linear.