Converting electricity to ammonia (NH3) involves several energy intensive steps that result in higher losses than a direct hydrogen economy. The primary losses occur during electrolysis, nitrogen fixation via the Haber Bosch process, and the eventual reconversion of ammonia back into electricity or heat.
First, the electrolysis stage converts electrical energy into hydrogen. Second, the Haber Bosch process requires significant thermal and mechanical energy to compress gases and facilitate the chemical reaction between hydrogen and nitrogen. This synthesis step introduces further thermodynamic inefficiencies. Finally, if the ammonia is used in a fuel cell or internal combustion engine, additional energy is lost during the cracking process or through heat dissipation during combustion.
In a direct hydrogen pathway, energy is primarily lost during electrolysis and compression or liquefaction. When comparing the two, the ammonia pathway typically incurs significantly higher round trip efficiency losses due to the extra chemical synthesis and reconversion stages. While ammonia is much easier to store and transport than liquid hydrogen, the energy penalty for its production and subsequent use must be weighed against the logistical benefits of its high energy density and existing maritime infrastructure.
