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Delivering green hydrogen for clean energy

Lightweight high-pressure vessels are crucial for enabling the transition to a hydrogen economy.

To meet growing demand from energy, transport, aerospace and defence sectors, we produce light and robust composite overwrapped pressure vessels (COPV) for safe, cost-effective storage and transport of green hydrogen and other gases.

Composite Overwrapped Pressure Vessels

CST Optimum supplies various sizes of Type III and Type IV COPVs, with end-to end design, manufacture and certification undertaken in-house.



Our Type III and IV COPVs are up to 5x lighter than Type I vessels, leading to improved fuel economy and greater vehicle range.


Made with demanding safety requirements, our COPVs are tested at every stage of the product lifecycle. The patented Polar Boss design enhances structural integrity with superior sealing of plastic to the metal interface.

High quality

All products are designed and manufactured under endorsed ISO9001 Quality Management systems with full material and production traceability to ensure every COPV performs as expected.

Fully certified

Our product certification is endorsed by the US Department of Transport. Australian regulation is currently dependent on international standards, testing regimes and certification schemes.

Long lasting

Our corrosion resistant design requires re-certification only every 15-30 years (unlike Type I steel vessels requiring re-certification in 3-5 years).

Cost effective

Whole of life cost compared to steel pressure vessels.
Ask us for a quote >

Full batch tracking & traceability

Throughout the production process for quality assurance and product safety.


Our COPVs are primarily used for hydrogen storage. However, they are suitable for the storage of other gases and for use in other applications.

Product range & specifications

Hydrogen COPVs: Type IV
Tank capacity [litres]H2 Capacity [kg]Diameter [mm (inches)]Length [mm (inches)]Mount TypePortTank weight [kg]
1.30.03114 (4.5)228 (9)N/ASingle-
7.50.17172 (6.8)475 (18.7)N/ADouble-
842.0416 (16)1041 (41)NeckDouble42
2044.8416 (16)2134 (84)NeckDouble84
3197.6416 (16)3048 (120)NeckDouble125
77018.2793 (31.2)2134 (84)NeckDouble205
98723.3793 (31.2)2647 (104.2)NeckDouble263

All hydrogen COPVs have:

  • Service pressure: 350 bar
  • Certification: HGV2, DOT, ISO11119-3 (pending)
Tank capacity [litres]GGEDiameter [mm (inches)]Length [mm (inches)]Tank weight [kg]Certification
816.8406 (16)889 (35)32.7NGV2, DOT
1159.7406 (16)1219 (48)48.5NGV2, DOT
988.3482 (19)863 (34)53NGV2, DOT
14011.8482 (19)1143 (45)69NGV2, DOT, ISO11439
19616.7482 (19)1524 (60)89NGV2, DOT
24620.7533 (21)1524 (60)108.9NGV2, DOT
74562.6736 (30.5)2184 (86)TBANGV2, DOT

All CNG COPVs have:

  • Service pressure: 250 bar
  • Mount type: strap or neck
  • Port: double

Under Development


CST Optimum’s multi-pack COPVs are currently under development and will be able to be configured into a single container, crate or trailer. Multi-packs will enable the rapid recharge of hydrogen storage for large applications.

Type V vessels

CST Optimum’s expert team have developed Type V COPVs. These liner-less all-composite vessels further reduce weight for specialised defence and aerospace applications. Please contact us for further information.