Comparison of energy consumption for various production methods for nitric acid (best available technology, and minimum energy consumption). The best available technology refers to industrial practice and laboratory results. * See the ESI.

Technology	Best available technology (MJ mol N−1)	Minimum energy consumption* (MJ mol N-1)
Thermochemical process (electrolysis-based Haber–Bosch + Ostwald)	0.615	0.3532
Thermal plasma (Birkeland–Eyde process)	2.4–3.17–9	0.72
Warm plasma (Gliding arc reactor)	2.433	0.534
Plasma with only vibrationally-promoted Zeldovich mechanism (only vibrational excitations in N2)	—	0.28