Review of solar energy for biofuel extraction

One of the most complex challenges of today is managing greenhouse gas emissions produced by excessive use of fossil fuels as energy source. With fossil fuels dominating the energy production, the sustainable and environmental problems will continue unless alternative sources of energy are put in place. Biomass is considered as a promising sustainable energy source which can be introduced to the energy mix. One way of converting raw biomass to higher value biofuels is following the thermochemical conversion processes, which include pyrolysis, gasification, torrefaction, combustion and distillation. However, these processes typically require heat energy to treat the biomass, which is often supplied from non-renewable energy sources. This greatly reduces the conversion efficiency and causes environmental problems. Utilization of solar energy for assisting the biomass conversion through thermochemical conversion process significantly improves the overall sustainability and process performance. This work reviews the solar based technologies and their application to solar assisted biomass utilization and conversion technologies. The review then discusses outcomes of different solar assisted biomass pyrolysis and gasification processes performed to date. It also presents the status of solar assisted distillation for improving ethanol concentration.