The importance of dynamic operation and renewable energy source on the economic feasibility of green ammonia

Abstract

Long-term chemical storage of renewable energy in green ammonia has the potential to create a carbon-free energy market and replace fossil fuels. Cost estimations of green ammonia production are normally based on large-scale renewable energy installments with plentiful and consistent energy, which are well suited for the capital-intensive and flexibility-constrained Haber-Bosh process. This study analyzes green ammonia production under a wide range of scenarios by balancing the two competing economic drivers: the maximization of overall ammonia production and the minimization of feed buffer storage. We demonstrate that the optimized cost of green ammonia production (i.e., optimum scheduling, energy curtailment, and design capacity) is strongly dependent not only on the renewable energy capacity factor but also, more importantly, on the seasonal variations, production scale, and ramping capabilities of the process (i.e., dynamic operation). These results demonstrate the shift in process optimization target from maximizing energy efficiency to decreasing costs, which will be prevalent when electrifying chemical processes.