Is liquid hydrogen the missing link for using fuel cells in transportation? There is a lot to unpack with that question. I’m not referring to the common practice of transporting hydrogen in the liquid state for delivery to a refueling station. I’m talking about filling tanks on trucks, trains, and planes with liquid hydrogen. Yes, -423° Fahrenheit, liquified, cryogenic, hydrogen. Two recent announcements, one from Hyzon and one from H2FLY, make me think that maybe there is a place for liquid hydrogen stored onboard.
The method of using liquid hydrogen to replenish fueling stations is sound. The energy density of liquid hydrogen (LH2) is far greater than gaseous hydrogen (GH2), even at high pressure. Demaco has a terrific blog post on the subject. The economics of GH2 simply don’t work for high consumption applications like refueling stations because the shipping costs are far greater than for LH2. If you apply the same principle of energy density, wouldn’t it make sense to use LH2 in the machinery that actually uses the hydrogen?
As an aside, I don’t see automobiles as a potential target market for this technology. Cars are simply not used enough to consume the hydrogen required to justify the cost. In fact, I don’t believe in the economics of FCEVs in general when compared to battery electric vehicles. Many EV users can charge at home and never have to visit a public charger. Until hydrogen filling stations are as common as gas stations, which may never happen, EVs will be the way to go.
That said, hydrogen fuels cells do work for high use vehicles. Shorter refueling times, larger payloads and longer range make fuel cells the superior choice over batteries for heavy duty and long haul trucks. I know that statement will get some on the defensive.
Today’s hydrogen fuel cell trucks use high pressure gas, so is using LH2 even practical? Hyzon seems to think so. Performance Food Group recently completed a demonstration with a Hyzon truck using LH2. Starting out in Temple, Texas, the truck completed deliveries to eight PFG customers near Dallas, travelling over 540 miles on a 16-hour continuous run that included temperatures over 100 degrees Fahrenheit. Hyzon believes they can reach up to 800 miles; that’s 60% farther than a fuel cell truck with GH2. Longer range and similar refueling times make it a better comparison to diesel trucks.
Chart Industries, the liquid tank maker, believes that long-haul and heavy-duty transportation is a key end-use for liquid hydrogen. Alstom, the locomotive manufacturer, has already deployed hydrogen trains in Europe and is considering how to implement LH2 for greater range.
The strongest market for LH2 may be in aviation. With its high density, LH2 requires fewer tanks. This reduces the weight and space allocated for the fuel. Both are key elements in the aviation business.
H2FLY recently completed the world’s first flight of an electric aircraft powered by LH2 rather than GH2, opening a new door of opportunity for zero-emissions long distance flights. H2FLY believes using LH2 can double the flying distance to 1500 KM (over 900 miles) and increase the payload capabilities of their current GH2 aircraft. The increase range is significant as it is one of the drawbacks to using hydrogen in aircraft.
When discussing the break though, H2FLY cofounder Professor Josef Kallo said, “This achievement marks a watershed moment in the use of hydrogen to power aircraft. Together with our partners, we have demonstrated the viability of liquid hydrogen to support medium and long-range emissions-free flight. We are now looking ahead to scaling up our technology for regional aircraft and other applications, beginning the critical mission of decarbonizing commercial aviation.”
As I mentioned in an earlier blog post, I’m skeptical of hydrogen fuel cells in aviation. However, I always attempt to keep an open mind. Accomplishments like the H2FLY flight may make me rethink my position. Perhaps liquid hydrogen may get others to rethink their position on fuel cells as well.
The Math on this will come down to a simple calculation of "Utility" delivered per pound of weight for a given Motive/Fueling solution. (BEV vs FCEV(GH2) vs FCEV(LHs)) The benefit on high use vehicles as you noted is where H2 has a benefit. Half of that statement is true because of H2's lower weight over BEV for High Use vehicles does not decrease the Utility of the vehicle. (Which BEV does). The use of LH2 may increase the gap between Utility of use between FCEV & BEV.