Australia’s Provaris Energy has revealed a gaseous H₂ floating storage concept that has been granted approval in principle by the American Bureau of Shipping (ABS).

The solution, dubbed H2Leo, has a design capacity range of 300 tons to 600 tons of H₂, expandable to up to 2,000 tons. The ASX-listed company said the unit is suitable for various H₂ supply chains and applications, including bunkering for the maritime sector, intermittent/buffer storage for green H₂ production, and long-duration storage for excess renewable energy.

The H2Leo will have two cargo tanks with independent isolation, safety valves, and manifolds for compressed H₂ transfer. ABS has conducted risk and safety workshops to assess and mitigate H₂ handling risks. Provaris said it will work with ABS for design approval, cargo tank testing, and construction. The H2Leo class will have a fixed beam and depth of 31 m and 17 m, respectively, with length and draft varying according to the specified cargo capacity.

The cost of large-scale static storage is estimated by external studies to be in the range of $1 MM/t to $2 MM/t of storage installed, while Provaris claims that the cost of its floating storage solution will target a capital cost of $200,000/t to $300,000/t.

“This cost difference could make onshore static storage cost-prohibitive for large-scale H₂ derivative projects, such as ammonia,” the company said.

The development of H2Leo will run parallel to the remaining engineering and approvals for its H2Neo carrier, targeting prototype testing and final class approval later this year, with the unit set to become available in 2025.