Small-Scale Biomass Gasification for Green Ammonia Production in Portugal: A Techno-Economic Study

Abstract

A renewed interest revolves around ammonia through its synthesis via renewable energy sources, promoting green ammonia as a genuine contender and preeminent carbon-free energy carrier within the hydrogen economy. A National Hydrogen Strategy has already been set by the Portuguese Government, focusing on decarbonizing the national industry, while substantially reducing natural gas and fossil fuel-based ammonia imports. This study delivers a techno-economic assessment of a small-scale green ammonia production facility using biomass gasification in mainland Portugal. An improved economic model combining the net present value (NPV), internal rate of return (IRR), modified internal rate of return (MIRR), payback period (PBP), and discounted payback period (DPBP) is set to determine the project feasibility. A Monte Carlo sensitivity analysis is implemented to gauge the risks associated with the venture. Several environmental considerations are also addressed concerning the carbon footprint of deploying a biomass-to-ammonia system compared to conventional fossil fuel-based ammonia. Under current market conditions, the power plant is predictably economically feasible with an NPV of 3714 k€, IRR of 24.32%, MIRR of 14.99%, PBP of 4.6 years, and DPBP of 5.8 years. The sensitivity analysis foresees affordable risks for investors, although investment loss is more likely to occur due to NPV failure, being remarkably sensitive to ammonia production and ammonia sales price fluctuations. Finally, the geographic location set for the biomass-to-ammonia power plant has the potential to enable a bioeconomy and circular economy framework for increased renewability and improved productivity, while promoting sustainable agricultural practices in the region.