On the other hand, as Fig. (b) shows, the LCCO2 emission from ammonia synthesis is affected the most by the efficiency of water electrolysis (EH2). It is because ammonia synthesis requires a large amount of electric energy for water electrolysis (see Section 2.2). The following most influential parameters are the long-term average of a potential PV electricity generation (PVout) and LCCO2 emission from PV panels (𝐶 ), related to the PV electricity. The next is 𝐶 .