Nationwide, about 60 hydrogen stations are in operation in the U.S., most built within the last 10 years. The technology for making, storing and dispensing hydrogen has rapidly changed in a decade, and will continue to make progress. The technology has stabilized to a point where the first codes and standards have been published, and others are in process.

Hydrogen stations have several options. Some stations make their fuel onsite, others have it delivered as a liquid and others have hydrogen delivered as a gas. Each type of station needs equipment for storing, compressing and dispensing hydrogen. Currently, the storage tanks must be above ground, although codes for underground storage are in the planning stages. Some existing stations store hydrogen on the canopy.

At a liquid storage station, hydrogen is produced elsewhere and cooled to become a liquid. A tanker truck transfers the fuel to the retail site and fills the storage tank. To be a liquid, hydrogen must be at a cryogenic temperature (-423°F). The storage tank is like a giant thermos; it does not require electricity.

As needed throughout the day, a valve on the liquid tank opens and the hydrogen flows into a small heat exchanger. The now-gaseous hydrogen flows into a compressor when it is compacted to 5000psi (H35) and then pushed into long cylinders. The compressed gaseous hydrogen is ready for dispensing into a vehicle. Hydrogen can be stored in the cylinders indefinitely without losing energy content.

When a customer turns on the hydrogen dispenser, the fuel flows from the storage tank through pipes that can be above or below ground. If the driver is dispensing fuel at H35, the fuel goes directly into the vehicle. If the driver is dispensing fuel at H70, the hydrogen first goes into another small compressor where the fuel is pre-cooled and compressed even more before dispensing. The hoses and nozzles are different for H35 and H70 fuel.

Other stations offer hydrogen that is delivered as a gas. The hydrogen is compressed and packed into cylinders at the point of production. A truck brings a trailer loaded with tubes to the station and leaves the tubes or the whole trailer in a designated area. The driver connects a feed on the first tube to the pipes that are connected to the dispenser. Although a gaseous station requires significantly less equipment, it cannot store as much fuel and the tube-trailer location must be integrated into the site design.

The third option is to make hydrogen at the station. Some stations have small reformers that use natural gas or biogas to make hydrogen onsite. The reformer is usually within a small building and the equipment to compress and store the hydrogen is nearby.

Other stations use electrolyzers and solar panels to make hydrogen from water and electricity. Electrolyzers look like commercial refrigerators and are attached to the water line. The equipment to produce, compress and store the hydrogen can be on the forecourt or on the canopy. Solar panels are connected to the grid, producing electricity for the utility during daylight hours, then the electrolyzer “buys back” the electricity to make hydrogen at night, when the demand—and rates—are lower. Currently available electrolyzers can make enough fuel for up to 50 vehicles a day.

Visit our station page to learn more about California’s hydrogen stations.