What Shipowners Should Know About Transitioning to Hydrogen
A practical guide for shipowners evaluating hydrogen propulsion: fuel cells vs. combustion engines, storage trade-offs, retrofit vs. newbuild, the IMO/EU ETS/FuelEU Maritime regulatory landscape, and where the funding actually is.
What Shipowners Should Know About Transitioning to Hydrogen
This is the guide we’d want if we were a shipowner sitting down to actually evaluate hydrogen for the first time — not a sales pitch, and not a repeat of the technical deep-dives elsewhere on this site, but the decision framework that ties them together: which propulsion path fits your vessel, whether retrofit or newbuild makes sense, what the regulatory clock actually requires, and where the money is.
1. Fuel Cells or Internal Combustion? Start Here.
The first fork in the road is propulsion technology, and the market has already answered it for most vessel sizes: PEM fuel cells power roughly 84% of the hydrogen fleet built through 2024, with hydrogen internal combustion engines (H2-ICE) taking the other 14%. That split isn’t arbitrary — it maps to vessel size and power requirement.
| If your vessel needs… | The market is telling you… |
|---|---|
| Under a few MW, frequent manoeuvring (ferry, tug, OSV, harbour craft) | PEM fuel cells — fast load response, zero NOx, commercially available today |
| Multi-megawatt shaft power (bulk carrier, tanker, large cargo) | H2-ICE is emerging as the only proven path — see J-ENG’s 5.6 MW two-stroke engine, the largest hydrogen engine demonstrated to date |
| Steady baseload power, tolerant of slow response (offshore platform hotel load) | Solid oxide fuel cells (SOFC) are the long-term candidate, but still pre-commercial as of 2026 |
Almost every hydrogen vessel today, regardless of which technology it uses, runs a hybrid architecture — fuel cells or engines paired with a lithium-ion battery buffer. The battery absorbs transient loads (manoeuvring, acceleration) so the fuel cell or engine can run closer to its efficient steady-state point. Budget for this pairing from the start; very few real vessels skip it. See our technology reference for the full efficiency, cost, and design-parameter comparison across all three technologies.
2. Storage: The Decision That Shapes Everything Else
Your storage choice — compressed hydrogen (CH2) or liquid hydrogen (LH2) — drives tank placement, hull arrangement, bunkering method, and route range, in that order of consequence.
| CH2 (350–700 bar) | LH2 (−253°C) | |
|---|---|---|
| Volumetric density | ~25–39 kg/m³ | ~71 kg/m³ |
| Best suited to | Short-sea, inland, small-to-medium vessels | Medium-to-large vessels needing real range |
| Design complexity | Lower — ambient temperature, Type III/IV tanks | Higher — cryogenic tanks, boil-off gas management |
| Current fleet share | ~20 of 50 vessels built through 2024 | 1 vessel (MF Hydra) at scale, growing newbuild pipeline |
There is no universally “better” option — MF Hydra chose LH2 because its route genuinely needs the range; most CTVs and harbour craft choose CH2 because they don’t. Get this wrong and you’re either carrying more cryogenic complexity than your route justifies, or you’ve built a vessel with real range but chosen a storage form that can’t deliver it.
3. Retrofit or Newbuild?
This is a straightforward economic question with an age cutoff. A vessel under roughly 5 years old with a dual-fuel or 4-stroke engine is a genuinely good retrofit candidate. Past 12–20 years, retrofit economics weaken fast — you’re paying conversion CAPEX against a shrinking remaining service life. Two-stroke engines require more extensive modification than 4-stroke or dual-fuel platforms already installed.
For a real-world CAPEX estimate on your own vessel and route, run it through our Feasibility Tool — it scores technical, economic, and regulatory fit in a few minutes and gives you a retrofit CAPEX range by vessel size, not a generic industry average.
4. The Regulatory Landscape
Three regulatory forces are pushing the transition simultaneously, and they compound rather than substitute for each other:
- IMO’s Net-Zero Framework introduces binding carbon pricing on ships above 5,000 GT starting 2028, with a member-state vote on the mechanism’s final form due in December 2026.
- EU ETS already taxes ships trading in European waters for their carbon emissions, at a coverage rate rising to 100% from 2027.
- FuelEU Maritime sets a declining GHG-intensity ceiling for energy used on board, independent of the ETS carbon price — a ship can comply with one and still fail the other.
None of these mandate hydrogen specifically. What they do is raise the cost of staying on conventional fuel every year, which is the actual mechanism that makes alternative fuels economically rational — not a hydrogen mandate, a diesel penalty. See our FAQ for direct answers on incentives, infrastructure, and compliance timing.
5. Funding and Subsidy Programs
Public funding for hydrogen maritime projects is real and substantial, but every programme requires the applicant to already have a credible project — funding accelerates decisions, it doesn’t make them for you.
| Programme | Coverage | Scale |
|---|---|---|
| EU Innovation Fund | 40–60% of project cost | €40 billion (2020–2030) |
| Norway Enova | Up to 80% | NOK 1.5 billion+/year — the world’s most aggressive maritime hydrogen funder |
| Netherlands Maritime Masterplan | Up to 40% | €165 million (2023–2030) |
| UK SHORE | Up to 70% | £448 million (to 2030) |
See our funding guide for programme-by-programme detail, current application windows, and eligibility criteria — this table is the summary, not the application.
6. Proven Suppliers and Technology Readiness
You don’t need to evaluate the entire market from scratch. Fuel cell suppliers with class-approved, commercially operating products include Ballard Power Systems, PowerCell, Nedstack, EODev, TECO 2030, Corvus Energy, and Vinssen — all with vessels in service today, not just on a datasheet. Cryogenic storage and transfer equipment comes from established suppliers like Chart Industries, Demaco, and Emco Wheaton. See our technology suppliers directory for the full list with type-approval status by vendor.
A Practical Starting Checklist
- Run your vessel and route through the Feasibility Tool — free, first-pass, technical/economic/regulatory scoring in minutes.
- Decide CH2 vs. LH2 based on route range, not on which one sounds more advanced.
- Check whether your vessel is a retrofit candidate (age, engine type) or whether this is a newbuild decision.
- Identify which funding programme(s) your flag state and trade region actually qualify for.
- Engage a classification society (DNV, Bureau Veritas, Lloyd’s Register) early for an Approval in Principle — this sets your regulatory roadmap before you commit capital.
- Browse the ships database and shipping companies directory for vessels and operators with a profile similar to yours — someone has probably already made most of these decisions for a comparable route.
Why This Matters
Every vessel ordered in the next decade will still be sailing in 2050 — fleet renewal runs at roughly 4% per year, so today’s engine and storage decisions are largely irreversible for the ship’s operating life. Getting the propulsion, storage, and funding fit right at the decision point matters more than moving fast; a wrong storage choice or missed funding window is a multi-decade mistake, not a one-year one.
Sources & Further Reading
- Technology reference — full fuel cell, H2-ICE, and storage comparison
- Funding guide — programme-by-programme detail
- Technology suppliers directory — vendors with type-approval status
- Ships database and shipping companies directory
- Feasibility Tool — free first-pass assessment for your vessel