Scenario based techno-economic study of surplus hydropower-based urea production from cement plant flue-gas captured using piperazine-absorption

This study seeks to assess the viability of a surplus hydropower-driven urea production plant incorporating a novel piperazine-absorption-based carbon capture system from cement plant flue gas in Nepal. It includes a formally unexplored comprehensive technological review, economic analysis, and sensitivity analysis, proposing an optimized pathway to alleviate the government's annual liability of 65.68 million USD from urea subsidies. The capital cost for the 500-ton capacity plant is 155.77 million USD, with hydrogen and urea units contributing 34.00 % and 32.22 %, respectively, and an annual operating cost of 78.90 million USD. The calculated levelized cost of urea is 513.74 USD per ton, demonstrating sensitivity to electricity costs, breaking even below 0.04 USD per kilowatt-hour energy. This allows for annual urea production up to 12,725.93 kilotons while achieving a significant 81.14 % reduction in global warming potential compared to conventional synthesis (0.46 kg CO<inf>2</inf> equivalent per kg of urea produced). This approach, presenting a competitive and streamlined alternative, addresses gaps in previous literature. Additionally, the study, for the first time, explores urea production potential in four energy-demand scenarios, offering insights to shape government frameworks for optimizing the food-energy nexus, supporting global energy transition goals, promoting circular economy in Nepal, and guiding similar resource settings in developing economies.