Optimization of Compression and Storage Requirements at Hydrogen Refueling Stations

The transition to hydrogen-powered vehicles requires detailed technical and economic analyses of all aspects of hydrogen infrastructure, including refueling stations. The cost of such stations is a major contributor to the delivered cost of hydrogen. Hydrogen refueling stations require not only dispensers to transfer fuel onto a vehicle, but also an array of such ancillary equipment as a cascade charging system, storage vessels, compressors and/or pumps/evaporators. This paper provides detailed information on design requirements for gaseous and liquid hydrogen refueling stations and their associated capital and operating costs, which in turn impact hydrogen selling price at various levels of hydrogen demand. It summarizes an engineering economics approach which captures the effect of variations in station size, seasonal, daily and hourly demand, and alternative dispensing rates and pressures on station cost. Tradeoffs in the capacity of refueling station compressors, storage vessels, and the cascade charging system result in many possible configurations for the station. Total costs can be minimized by optimizing that configuration. Using a methodology to iterate among the costs of compression, storage and cascade charging, it was found that the optimum hourly capacity of the compressor is approximately twice the station’s average hourly demand, and the optimum capacity of the cascade charging system is approximately 15% of the station’s average daily demand. Further, for an hourly demand profile typical of today’s gasoline stations, onsite hydrogen storage equivalent to at least 1/3 of the station’s average daily demand is needed to accommodate peak demand.