Fuel analysis that quantifies the amount of chemical energy stored as volatile matter (VM) and fixed carbon (FC) has been developed for solid fuels such as coal. The VM of a solid fuel is the portion released as gas (including moisture) by heating to 950°C in the absence of air for seven minutes; the FC is the mass remaining after the volatiles have been driven off, excluding the ash and moisture contents. Fuel analysis based upon VM content, ash, and moisture, with the FC determined by difference, is termed the proximate analysis of a fuel. Elemental analysis of a fuel, presented as C, N, H, O and S, together with the ash content, is termed the ultimate analysis of a fuel. The ratio of FC to VM provides an indication of the ease with which the solid fuel can be ignited and subsequently gasified, or oxidized, depending on how the fuel is to be converted. Representative proximate and ultimate analyses for many of the biomass crops considered in subsequent chapters are listed in Table 1.1.