[ ammonia ]
CAPEX , Haber-Bosch plant
CAPEX , alkaline electrolysis plant
183 M $ 486 M $
Fig . 4 . CAPEX for a green ammonia production plant
the auxiliary systems of the HB plant , including adopting electric compressors and systems to replace heat-dependent components in the conventional SMR-coupled HB , some of these challenges can be addressed . 7 coupling with an electrified HB cycle , ensuring continuous and seamless green ammonia production . One possible approach is employing a simulation-based optimization method .
Utilizing advanced software tools , mathematical techniques , and simulation-based optimization allows for the design of a cost-effective green ammonia production system . This capitalizes on solar hydrogen production and innovative control strategies for the electrified HB process . Partial adaptation of the production profile to match the seasonal availability of solar resources is one way to reduce production costs .
Operational challenges of solar ammonia
While solar ammonia presents a sustainable pathway , it poses operational challenges due to the dynamic and intermittent supply of solar energy . For instance , intraday and seasonal variations in hydrogen production can affect the adaptability of the inflexible HB process to solar PV ’ s variability . Here are two approaches to address these challenges : 1 . Addressing solar energy variability : Strategies such as energy storage solutions , grid integration , and demand-side management can ensure continuous HB operation during nighttime and periods of reduced solar irradiation , such as winter .
2 . Optimal sizing for solar hydrogen production and buffer storage : Achieving the right balance between solar hydrogen production and storage is crucial . Advanced analytics and simulation tools can aid in achieving the lowest levelized cost of ammonia ( LCOA ).
The primary goal of a solar ammonia plant is to overcome these challenges while maintaining a low LCOA . This necessitates optimizing the plant ’ s design to ensure that the configuration and size of subsystems are optimal . To achieve this , it is essential to optimize the sizing of a solar hydrogen production system and storage to enable effective
As an example , consider a solar hydrogen plant coupled to an HB plant following two operational scenarios : one with 100 % continuous HB operation and another with a seasonally adapted profile , as illustrated in Figure 4 .
Scenario 1 involves the HB plant running continuously at 100 % capacity , ensuring uninterrupted ammonia production . However , this requires significant seasonal hydrogen storage and oversizing of the solar and electrolyzer plants to accommodate the surplus of hydrogen during the winter when production does not meet the required mass flow for the HB process to operate continuously . This leads to a sharp increase in CAPEX and hydrogen production overshooting during peak solar months , resulting in considerable curtailment levels in such a scenario .
In Scenario 2 , a flexible approach is adopted , adjusting HB production by reducing the required inlet mass flow for the HB plant . This operational adaptation relaxes hydrogen production constraints while maintaining 24 / 7 plant operation . Consequently , ammonia production is lower compared to Scenario 1 , which also reduces curtailment . Implementing modulated HB operation during the winter allows for a storage
28 Hydrogen Tech World | Issue 12 | October 2023