Ammonia from solid fuels: A cost-effective route to energy security with negative CO2 emissions

This study investigates a potential solution to the global challenge of secure, affordable, and low-carbon energy supply: ammonia production from local coal and biomass resources with CO2 capture for negative emissions. Two innovative configurations; an E-gas gasifier with membrane-assisted water-gas shift and an air-blown MHI gasifier design, are compared with an oxygen-blown GE gasifier benchmark. Under the baseline cost assumptions of 2.5 euro/GJ for coal, 6.1 euro/GJ for biomass, and a CO2 tax of 100 euro/ton, the GE configuration reached a levelized cost of ammonia (LCOA) of 391.5 euro/ton, while the E-gas and MHI concepts showed 59.0 (-15.1%) and 18.6 (4.8%) euro/ton lower and higher costs, respectively. Subsequent benchmarking against alternative ammonia supply pathways showed that the energy security offered by the E-gas configuration comes at a premium of around 40% over ammonia imported at cost from natural gas exporting regions, which will be cheaper than liquified natural gas if the CO2 price exceeds 60.9 euro/ton. Since prices of imported energy are generally well above the cost of production, the carbon-negative energy security offered by the proposed plants can be economically attractive to importers with rising CO2 taxes. Thus, policy support for establishing local ammonia value chains can be recommended.