Environmental competitiveness evaluation by life cycle assessment for solid fuels generated from Sida hermaphrodita biomass

Highlights: • Env. impacts of Sida biofuels were compared to those of woody & Miscanthus biofuels. • 70–80% of compared process chains cause larger environmental impacts than Sida. • More advantageous environmental impacts are also given with lower yields of Sida. • Not all impact causes are accessible for impact lowering due to non-influenceability. As part of a comprehensive evaluation of the use of Sida hermaphrodita (hereafter referred to as Sida) biomass as a solid biofuel, a life cycle assessment (LCA) according to ISO 14040/14044 was carried out by means of a suitable cradle-to-gate system design. The supply and use of chips, pellets and briquettes was studied by internal and external comparisons to show competitiveness and improvement options. The results show fewer differences within the Sida process chain designs but larger distinctions to compared alternative biofuels such as wood or Miscanthus pellets. A major finding is that Sida process chains cause lower environmental impacts in comparison with alternative biofuels. The study identified hot spots within the Sida process chains and starting points for further improvement. A sensitivity analysis of important parameters, such as specific yield or heating values was performed. Because there are no similar investigations on the environmental impact of Sida used as a biogenic solid fuel to date this manuscript presents first results. So far, the results indicate that Sida provides a more sustainable option for the use of biomass in combustion processes in relation to environmental impacts.