Towards Sustainable Fertilizer Production: Cost Comparison of Flexible and Continuous Electrolytic Ammonia Production

Ammonia production contributes 1% of global carbon emissions due to energy-intensive hydrogen synthesis. To mitigate this, renewable-powered water electrolysis is a promising solution. While numerous studies have explored the use of hydrogen storage and grid backup to align renewable energy sources with the continuous operation of the HB process, recent industry efforts focused on increasing plant flexibility, adjusting the production to intermittent power inputs. In this study, we model and optimize two plant configurations— continuous and flexible. The aim is to determine the conditions under which flexible production reduces costs. Our results show that renewable resource availability has a significantly greater impact on LCOA than plant configuration. For the same configuration, LCOA differs by a factor of two across regions with low and high-capacity factors. Continuous plants have lower LCOA in solar-dominated regions (-13%). In contrast, flexible plants are more cost-effective in wind-rich regions (-12%) or ones with high-capacity factors for renewable production (-11%) due to their ability to maintain the minimum load with less reliance on batteries or grid imports. The lowest LCOA is 372 EUR/ton NH₃ in high-capacity regions, followed by winddominated areas (389 EUR/ton NH₃), both with flexible configurations.