Solar-hydrogen energy systems have received some attention in recent years as viable alternatives to the present fossil-fuel based energy systems. This paper presents an economic analysis of three hydrogen liquefaction systems with an associated cost comparison. The analysis takes into account the energy cost, operation and maintenance, and fixed charges on capital investment. Electrical requirements of the compressors or energy cost of a liquefier are prodemoninantly functions of the liquefier efficiency and are less dependent on the production rate required. Liquefaction costs in a large-scale liquid hydrogen plant depend primarily on the energy costs. Operation and maintenance costs, on the other hand, constitute; (1) plant payroll, (2) consumable supplies and equipment, (3) outside support services, and (4) miscellaneous costs. Finally, capital investment in a liquefaction system depends, to a great extent, upon the production rate, the types of liquefaction cycles 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 liquid hydrogen plant. The liquefaction cost was also shown to reach a value of $0.63/kg for the optimized large-scale type plant at a production rate of 30,000 kg/h when the cost of electricity is $0.04/(kW h).