Abstract
This article proposes a unified exergetic methodology for comparable, reproducible assessment and subsequent standardization of plasma processes. Based on the Second Law of Thermodynamics, it integrates exergy efficiency (Яех), specific energy consumption (Q sp ), exergy ignition cost (EIC), and environmental performance index (EPI) into a formalized KPI-stack. Unlike First Law criteria, the approach accounts for energy quality, irreversibility, and the non-equilibrium nature of plasma, distinguishing chemical, physical, and ionization components and quantifying exergy destruction at individual process stages. The methodology covers plasma ignition, gasification, reforming, and processing of gaseous, liquid, and solid hydrocarbon feedstocks and waste. Measurement, uncertainty assessment, and quality control are aligned with cited metrological requirements; environmental comparisons may incorporate life-cycle assessment. An oil-sludge case study compares conventional combustion at 1100 K with plasma-supported combustion at 1500-2000 K at a fixed process thermal power of 2000 kW. Calculations show differential exergy efficiency increasing from 0.546 to 0.636-0.675 and specific exergy losses decreasing from 18.27 to 14.48 MJ/kg. Environmental performance improves through a higher EPI and lower NO? emissions. Beyond thermal disposal, plasma processing produces valuable synthesis gas with total exergy reaching 156.7 MJ. The unified KPI-stack supports technology comparison, operating-mode optimization, and integration into regulatory and technical documentation.