Gasification is a partial oxidation process. The term partial oxidation is a relative term which simply means that less oxygen is used in gasification than would be required for combustion (i.e., burning or complete oxidation) of the same amount of fuel. Gasification typically uses only 25 to 40 percent of the theoretical oxidant (either pure oxygen or air) to generate enough heat to gasify the remaining unoxidized fuel, producing syngas. The major combustible products of gasification are carbon monoxide (CO) and hydrogen (H2), with only a minor amount of the carbon completely oxidized to carbon dioxide (CO2) and water. The heat released by partial oxidation provides most of the energy needed to break up the chemical bonds in the feedstock, to drive the other endothermic gasification reactions, and to increase the temperature of the final gasification products.