Development of direct carbon fuel cells opens new options for utlization of various carbonaceous fuels to produce electricity. Moreover, even some waste materials and by-products from industrial processes appear to be suitable for conversion in DCFC. An attractive opportunity is the use of carbon based by-products of methane plasma dissociation as a fuel. In this work comprehensive studies of two types of carbon fuels were performed, namely carbon powder (carbon A) produced by methane plasma dissociation and comercially available carbon black powder (carbon B). Before the electrochemical testing, both carbon fuels were characterized by X-ray, Raman, XPS/ESCA spectroscopy, thermal analysis (DTA, TG), electrical conductivity and other methods. Carbon A possessed larger particle surface area and lower ohmic resistance than carbon B, its purity was comparably high and ash content was low. Four different types of DCFCs were used during testing: all of them used solid electrolyte (8YSZ) and varied only anodic part of the cells. All the tests showed high degree of feasibility of the waste product of methane plasma splitting (carbon A) as a fuel for DCFC, very similar to the traditionally used as a reference carbon B.