Optimization-based analysis of integrated lignocellulosic biorefineries in Spain focusing on building blocks

Spain, in the framework of the European Green Deal, has set ambitious climate and energy goals for 2030. Lignocellulosic biorefineries can make a strong contribution to these goals; however, advanced biofuels generally cannot be produced in a profitable way compared to fossil and first-generation fuels. To address this problem, the efficient production of a wide range of bioproducts, not only biofuels and bioenergy, may be the solution. Therefore, a systematic evaluation of the near-term economic potential bio-building blocks (xylitol, sorbitol, succinic, glutamic, glucaric, levulinic, lactic, and itaconic acids) is presented. Many possible combinations of feedstock and conversion technologies can be considered feasible pathways to manufacture advanced biofuels and bio-based building blocks. To map the optimal groups of technologies in the framework of Spain's biorefineries, we apply a methodology based on a network optimization approach that combines minimum cost and energy criteria together with feedstock availability and demand constraints. The feedstocks analyzed are pine and eucalyptus residues and olive tree pruning wastes, being three largely available agroforesty residues in Spain. The results show that building blocks show good economic and energy performance compared to advanced transportation biofuels, and although their demand is much lower, they should be considered to improve the profitability of biorefineries. Secondly, advanced gasoline, bioethanol, hydrogen, and building blocks demands can be satisfied with pine, eucalyptus, and olive residues available in Spain. Finally, lactic acid production is profitable, but the remaining routes do not reach the break-even point, suggesting that further research is still needed.

Automated summary

In the framework of the European Green Deal, Spain has set ambitious climate and energy goals for the year 2030. The use of lignocellulosic biorefineries can contribute to these goals, but the production of advanced biofuels is not profitable compared to fossil fuels. To address this issue, the efficient production of a wide range of bioproducts is proposed. A systematic evaluation of the economic potential of various bio-building blocks is presented, and different combinations of feedstock and conversion technologies are considered. Pine and eucalyptus residues, as well as olive tree pruning wastes, are analyzed as available feedstocks in Spain. The results show that bio-based building blocks have good economic and energy performance compared to advanced biofuels and should be considered to improve the profitability of biorefineries. Pine, eucalyptus, and olive residues can satisfy the demand for advanced gasoline, bioethanol, hydrogen, and building blocks in Spain. However, further research is needed for routes other than lactic acid production to reach the break-even point.