NOVELTY - Composition comprises a processed biochar composition that comprises a solid renewable carbon fuel with characteristics that include an energy density of at least 17 MMBTU/ton (20 GJ/MT), a water content of less than 10 wt.%, and a water-soluble salt content i.e. decreased more than 60 wt.% on a dry basis from that of unprocessed organic-carbon-containing feedstock.    USE - The composition is useful as a combustible fuel for generating heat for cooking and heating, and a soil amendment to supply minerals for fertilizing soils used for growing agricultural and horticultural products, for the production of bio-oil and syngas, and as a coal substitute for devices that use coal as a feedstock to generate heat such as coal-fired boilers used to make electricity.    ADVANTAGE - The biochar composition is cleaner than coal, can be made in a cost-effective manner, and has low water and water-soluble salt content, thus reducing adverse corrosive wear and maintenance cleaning of the devices.    DETAILED DESCRIPTION - Composition comprises a processed biochar composition that comprises a solid renewable carbon fuel with characteristics that include an energy density of at least 17 MMBTU/ton (20 GJ/MT), a water content of less than 10 wt.%, and a water-soluble salt content i.e. decreased more than 60 wt.% on a dry basis from that of unprocessed organic-carbon-containing feedstock. The processed biochar is made from unprocessed organic-carbon-containing feedstock i.e. converted into the processed organic-carbon-containing feedstock with a beneficiation sub-system, and to the processed biochar with an oxygen-deficient thermal sub-system. An INDEPENDENT CLAIM is included for making the processed biochar composition (a solid fuel composition), comprising (A) inputting into a system comprising a first and a second subsystem an renewable unprocessed organic-carbon-containing feedstock that includes free water, intercellular water, intracellular water, intracellular water-soluble salts, and at least some plant cells comprising cell walls that include lignin, hemicellulose, and microfibrils within fibrils; (B) passing unprocessed organic-carbon-containing feedstock through the first sub-system, a beneficiation sub-system process, to result in processed organic-carbon-containing feedstock having a water content of less than 20 wt.% and a salt content i.e. reduced by at least 60 wt.% on a dry basis from that of the unprocessed organic-carbon-containing feedstock; and (C) passing the processed organic-carbon-containing feedstock through the second sub-system, an oxygen-deprived thermal sub-system process, to result in processed biochar.