From Carbondioxide to Crop - Comparative Costing of Green Fertilizer Production Routes for Ghana’s Agricultural Sector
Abstract
In light of rapidly increasing fertilizer demand across Sub-Saharan Africa and the global transition towards carbon-neutral and climate-resilient agricultural systems, green fertilizers produced using carbondioxide from non-fossil sources could offer a critical pathway to decouple food production from fossil-based inputs. While individual technologies such as point-source carbon capture or direct air capture (DAC) are increasingly studied, a comparative and system-oriented cost assessment of alternative carbondioxide supply chains for green fertilizer production remains largely absent from the literature—particularly in the context of emerging economies. This study presents a comprehensive techno-economic comparison of four distinct green fertilizer supply pathways: (i) on-site fertigation using locally generated nutrient streams, (ii) carbondioxide captured from existing industrial point sources, (iii) carbondioxide obtained via direct air capture, and (iv) biogenic carbondioxide derived from biomass-based processes such as fermentation or combustion. Ghana is selected as an exemplary case study due to its growing agricultural demand, emerging renewable energy sector, and relevance for future green fertilizer markets in West Africa. A detailed techno-economic analysis evaluates the cost structures and lifecycle emissions of these supply chains under current and future scenarios. Carbondioxide provision costs are found to vary widely depending on technology maturity and assumptions, ranging from 36–184 EUR/t for biogas-based sources and 277–433 EUR/t for DAC in 2030, with notable cost reductions projected by 2040. In parallel, fertigation—defined as the precise delivery of nutrients via irrigation systems—is examined as an efficiency-enhancing application strategy capable of substantially reducing overall fertilizer demand. Results indicate that green urea can deliver significant environmental benefits compared to conventional urea production when lifecycle emissions are considered. However, economic competitiveness and system-wide impact depend strongly on the choice of \co source, access to low-cost renewable electricity, and local infrastructure conditions. Beyond technological and economic optimization, successful deployment requires complementary investments in irrigation infrastructure and institutional capacity building to ensure accessibility for smallholder farmers. The findings highlight green urea as a promising component of sustainable agricultural intensification strategies in Sub-Saharan Africa.
