Partial oxidation or conversion of hydrocarbons to polymerized carbon suboxides can result in energy and/ or hydrogen production without CO2 emission. Despite the lower energy efficiency of this process in comparison with complete oxidation, this approach is promising because it avoids many problems related to fossil fuel combustion. Carbon suboxides, which are similar to the humic components of soils, may be used at a large scale as a soil conditioner. Addition of organic carbon to soil may counteract widespread carbon losses from soils due to climate change and land use patterns. This article discusses the conversion process thermodynamics for coal, biomass, and natural gas as the most abundant hydrocarbon feedstocks, as well as possible process organization and limitations. Conversion of methane into energy or hydrogen without CO2 emission has a thermodynamic efficiency as high as 65%.