Mapping biofuel field: A bibliometric evaluation of research output

Among sustainable and renewable energies, biofuels appear to be the most promising and attractive, and related research has been expanding along with an exceptional growth of scientific knowledge. Based on the Science Citation Index Expanded from the Web of Science, a bibliometric evaluation of research output was carried out to map research activities and tendencies of the global biofuel field. The results indicate that annual output of scientific articles rocketed during the past decade (2003–2012). The United States of America (USA) is leading biofuels research and collaborated mainly with other productive countries (China, United Kingdom, Germany, Canada and South Korea). In general, international collaborative publications resulted in more citations than single country publications. Institutional collaborations became increasingly prevalent over time and the 15 most productive institutions of USA tended to collaborate more with each other. Most research publications on biofuels appeared in the journals Biomass and Bioenergy and Bioresource Technology. Furthermore, biofuels research was based on combinations of multi-subject categories including "Energy and fuels", "Biotechnology and applied microbiology", "Chemical engineering", "Environmental sciences" and "Agricultural engineering". The keyword analysis confirmed the production of biodiesel from microalgae as the mainstream of recent biofuels research. Biorefinery was the most common technology for conversions of biological feedstock and life cycle assessment was the most popular tool of decision support to evaluate the sustainability of biofuel development.