Liquid Organic Hydrogen Carriers
Liquid organic hydrogen carriers (LOHCs) store hydrogen chemically in molecules that can be handled as liquids at ambient conditions: the carrier is loaded by hydrogenation at a central site, shipped using existing liquid fuel logistics, and catalytically dehydrogenated near the point of use to release hydrogen. They avoid high-pressure or cryogenic storage; examples include formic acid, methanol, ethanol and methylcyclohexane/toluene. An LOHC system needs a transport network for loaded and spent carrier plus hydrogenation and dehydrogenation processes, so its viability and cost depend jointly on hydrogen content, release conditions, catalysts and byproducts, reactor design, and plant size and location across the whole delivery chain.
Process and catalyst design for formic acid dehydrogenation (2025)
Using formic acid as the carrier, Sunshine and coworkers optimized the dehydrogenation step at a hydrogen refueling station with linked surrogates of catalyst, reactor and cost models (Sunshine et al. 2025). The jointly optimized design used a 5 nm Cu catalyst at 300 K and 100 bar and reached 14.01 $/kg H2 at a capacity of 1500 kg H2/day. A sweep of station capacity showed an economy of scale, with Pt the only feasible metal at small capacities (because of a reactor volume limit tied to capacity) and Cu the cheapest once feasible. Summary: sunshine2025a.
Formic acid in a hydrogen refueling chain (2025)
Yuan and coworkers compared formic acid delivery with compressed and liquid hydrogen delivery to ten 1000 kg/day, 700 bar refueling stations in California 100 miles from the terminal (Yuan et al. 2025). Even under optimistic assumptions, formic acid cost about $32/kg H2 against about $6 to 7/kg for the other two. The main costs were CO2-electrolysis synthesis, purification and closed-loop CO2 recycling, all amplified by the 4.4 wt% hydrogen content (each $1/kg of formic acid corresponds to about $23/kg H2). The authors concluded that short-distance supply to high-pressure stations is likely not an economic use case. They suggested screening carriers by hydrogen content, loading and release conditions, and byproducts, and pointed to long-distance shipping, seasonal storage and formate salts as scenarios where carriers might fare better. Summary: yuan2025.