Life Cycle Energy and Environmental Analysis Study of a Model Biorefinery in Thailand

There is commercial production of biofuels and biochemicals in Thailand. Yet there are no biorefineries at present. This study aims to evaluate the life cycle energy and environmental impacts associated with the production of biofuels and biopolymers for a model biorefinery in Thailand. Since there is currently no biorefinery in the country, secondary data sources from existing bioethanol and biopolymer plants were used for life cycle analysis (LCA). Sugarcane and cassava were chosen as feedstocks for the proposed biorefinery to produce bioethanol and polylactic acid (PLA). The system boundary was defined as cradle-to-gate with LCA methodology based on ISO 14040 series. Data were analyzed by using commercial LCA software, SimaPro 7.1, with Eco-Indicator 95 and CML 2 baseline 2000. The biorefinery system was modeled and its performance was evaluated for several factors such as fuel and biopolymer production, raw materials consumption, and total revenue generation for five scenarios. The results indicated that the biorefinery showed better performance in both global warming potential (GWP) and energy resources with increasing sugarcane usage. This was due to the use of bagasse and biogas as sources of fuel to generate electricity and steam by using a highly efficient electrical energy cogeneration process in the biorefinery. In contrast, increasing PLA production led to higher GWP and energy resource impacts due to high electricity and steam usage in the bioplastic production process. Finally, two Eco-efficiency parameters was developed in order to combine both environmental (GWP and energy resources) and economic (revenue) aspects by using average revenue gained and average impact associated. Among five scenarios studied, the results showed that S4 - high sugarcane usage and ethanol production - was the best scenario as it has higher eco-efficiency in both aspects.