Liquid Hydrogen Fast-Fill Pumps Promise Speedy Fueling Times
FirstElement Fuel makes the experience at the pump seamless for drivers. (Mindy Long for Transport Topics)
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OAKLAND, Calif. — Hydrogen fuel cell technology holds significant promise for over-the-road trucking applications, but refueling with hydrogen is much more technically complex than refueling with diesel fuel, experts said at a recent event to unveil a heavy-duty commercial hydrogen fueling station.
Hydrogen starts as a liquid at minus 423 Fahrenheit. “It is the second-coldest substance in the world,” said Shane Stephens, chief development officer for FirstElement Fuel, at the event. FirstElement will open what it’s calling the world’s first heavy-duty high-flow hydrogen fueling facility to the public in Oakland next month. The station is the first of about a dozen commercial hydrogen truck fueling locations FirstElement Fuel has planned.
Hydrogen can be stored as a liquid or as a gas in tanks with various pressure levels. Fuel cells use gaseous hydrogen, and to refuel vehicles, the hydrogen must be compressed in a controlled manner to between 700 and 900 bar.
FEF is using cryopump technology to convert liquid hydrogen into cold, compressed hydrogen in one step right at the pump at the Oakland facility. “The benefit of liquid at the downstream is you can take advantage of the high density and coldness. You need both of those to do fast fills,” Stephens explained.
Stephens
Using cryopump technology, FEF can fill a Class 8 truck in less than 10 minutes.
Liquid hydrogen is delivered via a tanker truck from a production facility. FEF has partnered with Air Liquide, which produces hydrogen at its facility in Las Vegas, and travel center and fuel hauler Pilot Flying J to deliver the fuel. The hydrogen is then delivered to a liquid hydrogen storage tank, which takes up less space than storing compressed hydrogen.
Air Liquide ranks No. 21, and Pilot Co. No. 20, on the Transport Topics Top 100 list of the largest private carriers in North America.
Stephens said the tanker truck technology to deliver hydrogen exists today, but like many parts of the hydrogen supply chain, production will need to ramp up to meet future demand.
Ghassan Sleiman, FEF chief technology officer, explained that the tanks to store liquid hydrogen are similar to a thermos, relying on insulation and a vacuum to maintain temperatures without needing extra energy. However, liquid hydrogen needs to be used regularly. As the temperature increases, “boil off” can occur, resulting in loss. “It may take several days to start boiling off, then it will boil off at 1% a day,” Sleiman said, adding that as long as at least 1% of a tank’s volume is used daily, boil off isn’t a concern.
Ghassan Sleiman, chief technology officer for FirstElement Fuel, said liquid hydrogen is stored at -423 Fahrenheit. (Mindy Long for Transport Topics)
Storage tanks can be vertical or horizontal, but Sleiman said vertical tanks pose greater permitting challenges relative to horizontal ones. He noted that there are strict codes and standards FEF must follow and said the company has done nearly 3 million fills at its locations without a safety incident — even when customers have made mistakes fueling.
Hydrogen is much lighter than air, so it dissipates rapidly if it is released rather than pooling on the ground like gasoline or diesel, Sleiman added.
FEF and Bosch Rexroth are working together on pump technology to improve the performance of FEF’s next generation of stations. “In partnership with Bosch, we’ve developed a high-volume, high-performance cryopump. It can unlock scale and volume needed for all hydrogen vehicles, but especially trucks,” Stephens said.
The nozzle attaches to the truck and utilizes infrared communication to communicate between the dispenser and the pump if there are any problems prior to fueling. (Mindy Long for Transport Topics)
David Hull, regional vice president of Bosch Rexroth, said there are critical safety issues equipment manufacturers have to address but noted that the risks are manageable. “There is a ton of misperception in the public about safety. We have work to do to get the perception changed,” he said.
The cryopump combines servohydraulic pump drives, software and a newly developed compression cylinder. Stephens said delivering liquid hydrogen and converting it directly at the pump has several benefits.
“Gaseous is limited by how much you can fit into a delivery trailer, and you can only unload about half of it,” Stephens said. “Liquid is dense. You can fit 10 times more in a trailer and can unload nearly all of it when you deliver to a station.”
That means facilities can hold more volume in a smaller footprint. “This product is going to be a revolution in cryopump technology that is available in this market,” Stephens said.
David Hull of Bosch Rexroth said there are critical safety issues equipment manufacturers have to address for hydrogen-fueled trucks but noted that the risks are manageable. (Mindy Long for Transport Topics)
Joel Ewanick, chairman of FEF, called the cryopump a game changer for hydrogen.
“This is the thing we’ve needed for decades,” he said. “This will help us make leaps and bounds and drive cost out of the system.”
FEF is testing the new pump at its proving grounds in Livermore, Calif., and plans to open its first stations with the Bosch Rexroth technology in late 2025 or early 2026, Sleiman said. FEF also will add the new pumps to the Oakland location in the future.
Partnerships have played a critical role in developing FEF’s fueling infrastructure, including at the Oakland site, which received funding from the California Air Resources Board and the California Energy Commission. FEF also worked closely with the Center for Transportation and the Environment and East Bay Municipal Utility District on the site.
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