Numerous conversion processes can be used to produce energy or gaseous, liquid, and solid fuels from biomass and wastes. In addition, chemicals can be produced by a wide range of processing techniques. Table 1 is a summary of the major feedstock, process, and product variables usually considered to develop a synfuel-from-biomass process. There are many interacting parameters and many possible feedstock-process-product combinations, but from a practical standpoint, not all are feasible. For example, the separation of the small amounts of metals present in biomass and the direct combustion of high-moisture content algae are technically possible, but energetically unfavorable.