AN ECONOMIC-ANALYSIS OF 3 HYDROGEN LIQUEFACTION SYSTEMS

Solar-hydrogen energy systems have received some attention in recent y ears as viable alternatives to the present fossil-fuel based energy sy stems. This paper presents an economic analysis of three hydrogen liqu efaction systems with an associated cost comparison. The analysis take s into account the energy cost, operation and maintenance, and fixed c harges on capital investment. Electrical requirements of the compresso rs or energy cost of a liquefier are prodemoninantly functions of the liquefier efficiency and are less dependent on the production rate req uired. Liquefaction costs in a large-scale liquid hydrogen plant depen d primarily on the energy costs. Operation and maintenance costs, on t he other hand, constitute; (1) plant payroll, (2) consumable supplies and equipment, (3) outside support services, and (4) miscellaneous cos ts. Finally, capital investment in a liquefaction system depends, to a great extent, upon the production rate, the types of liquefaction cyc les utilized, and the location of the plant. The analysis showed that the cost of liquefying hydrogen is lowest for an optimized large-scale type liquid hydrogen plant and is highest for a simple conceptual liq uid hydrogen plant. The liquefaction cost was also shown to reach a va lue of $0.63/kg for the optimized large-scale type plant at a producti on rate of 30,000 kg/h when the cost of electricity is $0.04/(kW h). ( C) 1998 International Association for Hydrogen Energy.