Benefit-cost analysis of enhanced rock weathering in Japan using experimentally derived agronomic responses and site-specific supply-chain parameters

Enhanced rock weathering (ERW) is a carbon dioxide removal technology that helps mitigate climate change while providing agronomic benefits. However, its feasibility depends on site-specific supply chain conditions and crop responses, and project-level financial performance remains underexplored. This study presents a site-specific assessment of ERW using life cycle and techno-economic analysis and calculates conventional investment indicators (net present value and break-even conditions) by constructing datasets incorporating quarry mineral composition, experimentally derived grinding energy, and geographic information systems-based transport distances. Agronomic co-benefits were evaluated using cassava field experiment data from previous literature, together with greenhouse experiments conducted in this study, showing 18–30% yield increases for olivine and 0–6% for basalt relative to untreated controls, which were converted into economic revenue. ERW scenarios for 18 Japanese quarry sites were evaluated over 20 years, assuming 2000 t-rock annual spreading. Crushing and grinding were the main emission sources, accounting for 53.8 kg CO2-eq t−1 rock yr−1, while transport emissions ranged from 0.88 to 38.27 kg CO2-eq t−1 rock yr−1, depending on distance. Highly reactive olivine sites achieved net CO2 removals of up to 1077 kg CO2-eq t−1 rock yr−1. In contrast, three basalt sites indicated ineffective CO2 removal due to low mineral reactivity and higher process-related emissions. Under base-case assumptions, net present value analysis incorporating agronomic co-benefits and carbon credit revenue showed that olivine sites achieved positive direct profitability, whereas basalt sites did not reach break-even, indicating that higher crop selling prices or carbon credit values are required to achieve profitability.