With the extrapolated data under 50 bar, we assumed that renewable energy is utilized to produce ammonia at a small scale locally: the production scale is 5 tonnes/day, and the electricity cost is 0.273 USD/kWh bearing photovoltaics and rechargeable battery. Figure shows the breakdown of the total cost for the ammonia synthesis loop under the situation. If the durations of new catalysts are 10 years, the total cost of Ru/Ba-Ca(NH2)2 is smaller than conventional catalysts. Therefore, the new catalysts are advantageous if electricity is pretty high, the production scale is small, and the catalyst duration is long. The former two points are the characteristics of green ammonia synthesis, and thus the new catalysts are suitable for green ammonia production. The result when the electricity cost is 0.0683 USD/kWh at a 5 tonnes/day scale is shown in Supplementary Information, indicating lower price is not suitable for new catalysts. Based on the results, the newly developed catalysts are advantageous for green ammonia synthesis. However, it requires the long durability of the catalysts, such as 10 years. Meanwhile, we did not consider recycling or reactivating catalysts, which mitigate the catalyst cost. Therefore, the investigation of these processes will also be critical.