Techno-economic and Environmental Assessment of Activated Carbon Electrodes for Supercapacitors from Oil Palm Leaves

Activated carbon (AC) has become widely favored due to its exceptional physicochemical characteristics and its capacity to fabricate electrodes. However, there have been limited studies on the environmental and economic impacts of AC supercapacitor production. This study investigates the environmental and economic impacts of AC made from oil palm leaves through hydrothermal carbonization and chemical activation. Experimental work was carried out to generate input data for the mass and energy balance, including processing temperature and AC yield. A techno-economic analysis highlights the significant economic potential of incorporating AC production into biomass processing. Different scales of production, ranging from 720 to 1080 tons per year of oil palm leaves, are compared in terms of economic feasibility. All processes are calculated based on material and energy balance, and a thorough cash flow analysis is conducted to estimate profitability metrics. The results show that all cases yield positive net present values (NPV), indicating profitability. The price of AC emerges as the most critical factor determining the viability and feasibility of an AC production facility. The minimum selling prices (MSP) of AC samples range from 10.50 to 13.40 USD per kg. Regarding environmental impacts, the life cycle assessment (LCA) employs a cradle-to-gate system boundary approach to evaluate the system's environmental sustainability. Environmental impact categories are assessed using the ReCiPe 2016 (H) midpoint impact assessment methodology. The study reveals that the process has environmental impacts, including marine ecotoxicity, freshwater ecotoxicity, freshwater eutrophication, and human toxicity, primarily due to the use of KOH in the chemical activation stage. This study highlights the practical advantages and benefits of AC production in terms of economics, environmental sustainability, and waste management.