At this demonstration stage of the heavy-duty hydrogen market, prefabricated hydrogen fuelers offer a potentially cost-effective refueling option due to the high capital investment and development time for a permanent heavy-duty refueling station. Prefabricated hydrogen refuelers are preferred for modest-sized truck fleets (up to 10 trucks) due to their ease and speed of implementation. These devices are complete storage and dispensing devices either containerized or mounted on a truck-trailer chassis and are plug-and-play. Hydrogen can be stored either as a liquid or a pressurized gas. Liquid is currently preferred due to the larger storage capacity of 1000 – 2500kg.
While permitting of these units can be faster than a permanent station as site requirements are minimal (consisting of a concrete pad for placement and an electrical connection to the grid for power) and the 2023 update to national fire code contains specifications for these types of installations, Texas fire code is based on a 2015 version and therefore those benefits do not translate.
These fueling devices operate similarly to their permanent counterparts with some modifications to simplify their design (refer to the “hydrogen station design” section). The liquid storage/ gaseous dispensing systems are virtually identical their permanent-station counter-part, where a cryopump, installed inside the liquid hydrogen storage container, pressurizes the liquid hydrogen to the needed pressure and when vaporized, the gaseous hydrogen is at the correct dispensing pressure.
The gaseous storage/ gaseous dispensing unit are designed specific to the truck fleet that they will be serving. If the requirement is 70MPa fueling, then the unit requires hydrogen storage compatible with 90MPa storage, which does away with the need for a separate compressor. It does require a chiller, so the hydrogen is dispensed at the appropriate temperature.