DNV: Hydrogen Ship Leaks Need Secondary Enclosures
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- DNV's final study for EMSA recommends secondary enclosures around all hydrogen leak sources, including on open deck, specifically to prevent leaks from spreading uncontrollably — departing from reliance on buoyancy and open-air dispersion as the primary safety case.
- The EMSA guidance is explicitly non-mandatory and advisory, designed to support practical design solutions for hydrogen-fueled ships rather than prohibit them, but it diverges from draft IMO interim guidelines in ways that carry commercial weight.
- Hydrogen requires stronger safety barriers than LNG, alcohol fuels, or batteries, adding cost across four layers: direct equipment (secondary enclosures, double-walled piping, gas detection), engineering (CFD, risk assessment, class engagement), operating (inspections, training, bunkering), and infrastructure (full hydrogen value chain).
- The Vestfjorden (Lofoten) ferry project — a NOK 4.98 billion (€450 million), 15-year contract between the Norwegian Public Roads Administration and Torghatten Nord — involves two 117-120m ferries designed to run on a minimum 85% hydrogen, consuming 5-6 tons per day across a roughly 90-100 km route.
- The Lofoten ferries' public design philosophy concentrated all hydrogen installations on the uppermost deck so any leaked gas would disperse upward and away from the vessel — an assumption now under pressure from DNV's guidance favoring physical secondary containment over open-deck dispersion.
- PowerCell's fuel-cell supply contract for the Lofoten ferries is valued at €19.2 million for about 13 MW of installed power, while the dedicated Bodø hydrogen project, backed by GreenH and Luxcara, plans a 20 MW electrolyser producing up to 3,100 tons of green hydrogen annually.
- At Statistics Norway's Q2 2025 industrial electricity price of 40.1 øre/kWh, the Bodø electrolyser's electricity input alone works out to roughly NOK 22.7/kg of hydrogen, or about NOK 45 million (€4.0 million) per year for the ferry service — before capital recovery, plant O&M, compression, and bunkering losses.
Why it matters: The DNV guidance does not ban hydrogen ships, but it forces designers toward more containment, more automation, and more class engagement — costs that compound across every subsystem. For the €450 million Lofoten ferry project, which already relied on upward dispersion as a primary safety argument, the emerging sector-wide consensus toward secondary enclosures could trigger design changes, re-engineering, or change orders on a flagship European hydrogen deployment, while battery and methanol alternatives continue to advance on simpler regulatory and infrastructure footing.
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