Low-Pressure, Large-Volume Hydrogen Storage

Not every hydrogen application needs ultra-high pressure.
In fact, many large-scale systems—production sites, marine platforms, and refueling depots—benefit from storing hydrogen safely and efficiently at moderate pressures (20–30 bar).
Flexyshell modules make this practical, economical, and scalable.

Big Volume, Low Pressure — Real Efficiency

A single Flexyshell vessel about 0.8 m in diameter and 30 m long holds roughly 15 m³ of gas.
At 25 bar operating pressure, that’s about 25 kg of hydrogen—and because the vessel remains slightly pressurized (around 4 bar) even when “empty,” it keeps its structural form without needing rigid reinforcement.

Flexyshell vessels are self-supporting: their tendon network and end-dome structure let them stack vertically, forming compact, stable storage towers without heavy frames or cradles.

A cluster of 100 such vessels, occupying roughly 130–150 m², can safely store about 2.5 tonnes of hydrogen.
That’s a significant storage capacity—achieved without compressors running at 700 bar or massive cryogenic tanks.

Why Low Pressure Works

Low-pressure hydrogen storage brings a surprising number of engineering and economic advantages:

  • Lower Energy Demand – Compressing hydrogen to 200 bar and above for comparable steel tanks consumes 1,500–2,000 kWh per tonne.
    Staying near 25 bar saves that energy and simplifies operations.

  • Simpler, Larger Tanks – The flexible wall + tendon system supports large diameters without massive wall thickness.

  • Inherently Safe – Operating pressures are far below the levels that cause brittle fracture or violent rupture.
    Even a full depressurization event releases limited energy.

  • Dual-Use Structures – Large, low-pressure modules can be built into foundations, marine pontoons, or energy hubs, storing hydrogen while carrying loads.
    This “structure + storage” synergy is unique to Flexyshell’s tension-based architecture.

Efficiency in Simplicity

By separating hoop and axial loads, Flexyshell achieves a practical gravimetric efficiency of around 1 % hydrogen by total mass — meaning the stored hydrogen weighs about one hundredth of the vessel itself.
Conventional steel tanks can reach slightly higher numbers, about 1.5 %, but only by storing hydrogen at pressures ten times higher (200–250 bar). Flexyshell achieves similar performance at just 25 bar — with lighter, recyclable materials, lower fabrication cost, and vastly simpler logistics.

The Takeaway

High-pressure isn’t the only path to efficiency.
Flexyshell modules make low-pressure hydrogen storage viable, scalable, and inherently safe—ideal for stationary hubs, offshore platforms, or marine systems where demand for compact space is lower and safety, cost, and simplicity matter more than squeezing every last bar of pressure.