How to Size a Hydrogen Refueling Station？

• Daily demand in kg/day is the starting point, not the final station size.
• Peak vehicles per hour and back-to-back fills usually drive compressor, cascade storage and dispenser requirements.
• Compressor capacity and high-pressure storage are interdependent: more buffer storage can reduce short-term compressor demand, while a larger compressor may reduce required buffer capacity.
• Tube-trailer pressure falls during unloading, so sizing must use the expected inlet-pressure range and usable hydrogen inventory.
• H35 or H70, vehicle tank size, fueling protocol and delivery temperature affect station architecture.
• Final equipment sizing requires dynamic simulation and engineering review; a spreadsheet calculation is only an initial screening tool.

“Station capacity” is often stated in kg/day, but buyers should distinguish four different measures:

• Daily throughput: total hydrogen dispensed during an operating day;
• Peak-hour demand: hydrogen required during the busiest hour or fueling window;
• Single-fill requirement: hydrogen delivered to one vehicle;
• Back-to-back capacity: consecutive fills the station can complete before pressure recovery becomes necessary.

Two stations can both dispense 500 kg/day but require different equipment. A depot fueling vehicles gradually overnight has a different load profile from a public or logistics station receiving several vehicles in one short window.

The first sizing question is therefore not simply “How many kilograms per day?” It is “When must those kilograms be delivered?”

Step 1: Calculate Daily Hydrogen Demand

Use this screening equation:

Daily hydrogen demand = vehicles per day × average hydrogen per fill × fills per vehicle per day

Then account for realistic fleet utilization, future growth and operational reserve separately. Avoid hiding every uncertainty inside one large safety factor; record each assumption so it can be reviewed later.

For example, 20 buses receiving an average of 30 kg once per day create an initial demand of 600 kg/day. This figure does not yet determine the compressor or storage size because it says nothing about the fueling schedule.

Step 2: Define the Peak Fueling Window

Assume five of those buses must each receive 30 kg within 90 minutes:

Screening peak demand = 5 × 30 kg ÷ 1.5 hours = 100 kg/hour

This 100 kg/hour figure describes the vehicle demand during that window, not automatically the required compressor nameplate flow. The station may meet part of the peak from high-pressure storage while the compressor replenishes the banks before, during and after fueling.

Record:

• Maximum vehicles arriving in 15, 30, 60 and 120 minutes;
• Required hydrogen per vehicle;
• Allowed fill time;
• Time available for storage recovery; and
• Whether two vehicles must be fueled simultaneously.

Station Sizing Input Worksheet

Step 3: Confirm the Hydrogen Supply

The station may receive gaseous hydrogen from hydrogen tube trailers, liquid hydrogen, a pipeline or on-site production. Each supply mode creates different storage and compression conditions.

For tube-trailer supply, provide the maximum and minimum expected inlet pressure, usable hydrogen per delivery, trailer changeover time and delivery frequency. A compressor that performs well at the initial trailer pressure may deliver less flow as the trailer empties. Nominal trailer capacity alone is therefore not a sufficient sizing input.

On-site production must be coordinated with the electrolyzer or production rate, buffer storage, operating schedule and backup supply. A production system sized to average daily demand may still need storage to cover peak fueling.

Step 4: Balance Compressor and Cascade Storage

Compressor and storage sizing should be evaluated together. A DOE-supported Argonne study found a clear trade-off: larger high-pressure buffer storage can support sequential fills while allowing more time for a smaller compressor to recharge; a higher-flow compressor may reduce the required buffer storage for the same demand. The optimum depends on daily demand, hourly variation, vehicle tank characteristics, costs and component life. See the peer-reviewed compression and storage optimization study.

A hydrogen storage cascade system divides storage into pressure banks. During a fill, the control system uses suitable banks as vehicle pressure rises. Sizing must check how many complete fills are possible before the highest-pressure bank can no longer meet the required condition.

Step 5: Select Dispensers and Cooling Capacity

Dispenser count should follow the peak schedule, not the daily total. Two dispensers do not necessarily double station throughput because they may compete for the same storage and compressor capacity.

Confirm whether the project needs H35, H70 or both. Review vehicle storage capacity, maximum mass flow, target fill time, simultaneous operation and the applicable fueling protocol. For light-duty fueling, SAE J2601 process limits account for delivery temperature, pressure ramp, initial tank pressure and ambient conditions. Heavy-duty fueling requires the appropriate vehicle and protocol basis.

The 35 MPa vs. 70 MPa hydrogen fueling systems guide explains these pressure-class differences in more detail.

Step 6: Validate the Complete Station Dynamically

Simple equations are useful for screening, but a final design should simulate the complete duty cycle. The model should test trailer depletion or production variability, compressor performance, cascade-bank switching, vehicle arrivals, thermal conditions and equipment downtime.

Useful authoritative tools include:

• Argonne HRSAM, which evaluates station configurations and demand profiles;
• NREL H2FillS, which models transient pressure, temperature and mass flow from station storage through the dispenser to the vehicle; and
• HySCapE, which estimates hydrogen station capacity using a defined fueling-demand profile.

These tools reinforce the central sizing principle: component nameplate values must be tested as an operating system.

Sizing Only From kg/day

Average daily demand hides the peak. Always model the busiest fueling period.

Using Nominal Supply Capacity

For delivered gas, use the pressure-dependent usable inventory and compressor inlet range—not just the trailer’s headline capacity.

Treating Compressor Flow as Dispenser Flow

The dispenser may draw from cascade storage at a different instantaneous rate from the compressor. Both recovery and drawdown must be checked.

Ignoring Growth and Maintenance

Define a realistic expansion case, but avoid oversizing every component from day one. Consider modular storage, additional dispensing positions and planned redundancy.

Rein supplies Hydrogen Refueling Station Equipment including compressors, hydrogen storage cascades, unloading and filling equipment, sequence control valve groups, dispensers and station controls. Rein also provides system integration and hydrogen engineering services for project-specific requirements.

For an initial configuration review, provide:

• Vehicle type and H35/H70 requirement;
• Vehicles per day and hydrogen per fill;
• Peak vehicles per hour and target fill time;
• Hydrogen supply mode and pressure range;
• Project country and site conditions; 
• Required scope: equipment, integration, commissioning or EPC.

Request a Station Sizing Review

How many kilograms per day should a hydrogen station supply?

Multiply vehicles per day by average hydrogen per fill and fills per vehicle, then add separately justified growth and operating allowances. Final capacity must also pass the peak-window and recovery analysis.

How large should the hydrogen compressor be?

There is no universal ratio between compressor flow and kg/day. Compressor sizing depends on inlet pressure, discharge pressure, storage capacity, operating hours, recovery time, redundancy and the peak fueling profile.

How much cascade storage does a station need?

Enough to support the required consecutive fills and pressure sequence while the compressor restores the banks. Dynamic modeling is normally required because usable storage changes with pressure and vehicle conditions.

Can one dispenser serve a fleet station?

Possibly, if the available fueling window and reliability target allow it. Multiple dispensers may be required for simultaneous operation, shorter queues or redundancy, but the shared upstream