Techno-economic assessment of utilization pathways for rice straw: A simulation-optimization approach

Countries all over the world try to promote the use of biomass in order to reach environmental goals. However, existing technologies and products contain many uncertainties that make the assessment of economically and environmentally sustainable utilization pathways very challenging. One country with an extremely high biomass potential is Thailand, where the strong agricultural sector produces large amounts of agricultural residues, such as rice straw. Therefore, the objective of the article is to analyze different utilization pathways for rice straw potentials in central Thailand. Four different technologies (combustion, gasification, pyrolysis, and pelletizing) are assessed, and economically favorable applications are investigated. Two types of uncertainties are included within a hybrid simulation-optimization approach. First, uncertainties for technological and economic factors of each component of the supply chain are included in a Monte Carlo simulation. Second, uncertain framework conditions such as political goals, demand for bioenergy, or fuel prices are included as scenarios in the stochastic optimization model, which at the same time processes the results of the Monte Carlo simulation. This approach allows for the evaluation of the percentage of the rice straw potential in central Thailand that could be utilized from an economic perspective. However, the results indicate that only 46-65 percent of the rice straw could be processed in a profitable way. Considering the analyzed technologies, the production of pyrolysis oil was identified to be the economically best utilization path for rice straw, which is in line with Thailand's target of 0.5 million liters of pyrolysis oil to be used in 2036 per day. (C) 2019 Elsevier Ltd. All rights reserved.