The spark-discharge plasma, generated between tubular and rotary-disc electrodes using a sine-wave high voltage with 5 kHz frequency, was explored for CO, reforming of CH(4). Based upon the investigation on the effects of specific energy input and CO(2)/CH(4) ratio, the energy costs (EC) and fuel-production efficiencies (eta) at various CO(2)/CH(4) ratios (r) in the same conversion range were compared and accordingly their sequences were given: EC(CH4) (r = 0.5) and EC(CO2) (r = 3) are the lowest; eta(r = 0.5) is the highest. Compared with other nonthermal discharge techniques, the kilohertz spark discharge exhibits low EC and high fuel-production efficiency, especially at high total-carbon conversions. Preliminary investigation on partial oxidation and CO(2) mixed reforming at (O(2) + CO(2))/CH(4) = 0.5 exhibited high H(2)/CO ratio (nearly 2) and low total-carbon EC (0.59-0.96 MJ/mol, 58-77% of total-carbon conversion, and O(2)/(CO(2) + O(2)) = 0.8). (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 2854-2860, 2011