Published 25 April 2026 · last updated 28 April 2026

RFNBO under EU Rules

Renewable Fuels of Non-Biological Origin (RFNBO) are liquid or gaseous fuels produced from renewable energy sources other than biomass, principally green hydrogen (produced by water electrolysis using renewable electricity) and its derivatives green ammonia, e-methanol and e-LNG (produced by combining green hydrogen with nitrogen, captured CO2 or other feedstocks). The EU regulatory framework for RFNBO under the Renewable Energy Directive III (RED III) and the implementing Delegated Act 2023/1184 (renewable electricity criteria) and Delegated Act 2023/1185 (GHG savings methodology) sets strict criteria that determine whether a given fuel batch qualifies as RFNBO: (i) additionality (the renewable electricity must come from new installations not benefitting from other public support); (ii) temporal correlation (the renewable electricity must be matched to the hydrogen production on an hourly basis from January 2030, after a transitional monthly-matching period from 2024 to 2029); (iii) geographical correlation (the renewable electricity must be produced in the same bidding zone as the hydrogen plant, or in an interconnected zone with proven physical electricity flows); (iv) 70% GHG savings versus the fossil comparator under the WtW methodology of Annex V of RED. RFNBO classification confers significant regulatory benefits in marine fuel: the FuelEU Maritime GHG intensity multiplier of 2x (each MJ of RFNBO counts as 2 MJ for compliance through 2034), eligibility for the RED III Article 25 1% RFNBO sub-target for marine fuel, eligibility for EU ETS zero-rating, eligibility for the IMO Net-Zero Framework Tier 1 / Tier 2 GHG Fuel Intensity (GFI) compliance and inclusion in the Hydrogen Bank auction support scheme. The framework is the principal regulatory anchor for the emerging marine methanol and ammonia bunker markets, and is closely watched by LNG dual-fuel operators considering the future migration to e-LNG. ShipCalculators.com hosts the principal computational tools: the RFNBO eligibility calculator, the RFNBO GHG savings calculator, the hourly matching certificate calculator, the FuelEU RFNBO multiplier calculator, the WtW intensity calculator and the GFI compliance calculator. A full listing is available in the calculator catalogue.

Contents

Background

Why RFNBO matters for marine fuel

The marine sector is at the start of a multi-decade transition from conventional fossil HFO and MGO to lower-carbon and ultimately near-zero-carbon fuels. The credible candidate alternative fuels are LNG, methanol, ammonia and biofuels; each of these alternative fuels can be produced through multiple pathways with very different WtW intensity outcomes:

Methanol can be fossil methanol (from natural gas, WtW intensity comparable to HFO), bio-methanol (from waste wood, WtW intensity approximately 8 to 12 g-CO2eq/MJ) or e-methanol (from green hydrogen + captured CO2, WtW intensity approximately 5 g-CO2eq/MJ).
Ammonia can be grey ammonia (from natural gas, WtW intensity higher than HFO), blue ammonia (from natural gas with CCS, WtW intensity approximately 25 to 35 g-CO2eq/MJ) or green ammonia (from green hydrogen, WtW intensity approximately 5 to 15 g-CO2eq/MJ).
LNG can be fossil LNG (WtW intensity approximately 75 to 100 g-CO2eq/MJ depending on methane slip) or e-LNG (synthetic methane from green hydrogen + captured CO2, WtW intensity approximately 5 to 15 g-CO2eq/MJ).

The RFNBO classification is the legal instrument that distinguishes the lowest-WtW pathway (the fully renewable, fully additional, fully matched pathway) from the higher-WtW alternatives. Without RFNBO classification, a fuel batch is assessed only by its certified WtW intensity value; with RFNBO classification, the fuel benefits from the doubled multiplier and from regulatory eligibility in the RED III and FuelEU Maritime frameworks.

For a vessel owner contemplating an investment in methanol or ammonia dual-fuel engine capability, the available bunker supply is dominated in the near term by lower-grade methanol and ammonia (fossil and blue), with RFNBO-grade methanol and ammonia entering the market only from approximately 2026 to 2028 in commercial volumes. Understanding the RFNBO eligibility framework is essential for forming a credible long-term decarbonisation strategy.

Regulatory architecture

The RFNBO regulatory architecture in the EU comprises several interconnected instruments:

Directive (EU) 2023/2413 (RED III): the third recast of the Renewable Energy Directive, in force from November 2023, defining RFNBO and setting the 1% RFNBO sub-target for transport (Article 25(1)(b)).
Commission Delegated Regulation (EU) 2023/1184: the Renewable Electricity Delegated Act, defining the additionality, temporal correlation and geographical correlation criteria for renewable electricity used in RFNBO production.
Commission Delegated Regulation (EU) 2023/1185: the GHG Savings Delegated Act, defining the methodology for calculating the GHG emissions of RFNBO and the 70% GHG saving threshold.
Regulation (EU) 2023/1805 (FuelEU Maritime): the marine fuel intensity regulation, applying the RFNBO multiplier of 2x to RFNBO-classified fuels.
Regulation (EU) 2023/959 (EU ETS Maritime): the EU Emissions Trading System extension to maritime, treating RFNBO at zero g-CO2/MJ for ETS surrender.
EU Taxonomy Regulation (2020/852): the green-finance taxonomy, with sustainability criteria for RFNBO production aligned with RED III.

The framework also interacts with non-EU instruments:

UK RTFO (Renewable Transport Fuel Obligation): the UK’s analogue framework, with similar but not identical RFNBO criteria.
US Inflation Reduction Act (IRA) Section 45V production tax credit for clean hydrogen: the US federal subsidy framework, with strict additionality, hourly matching and geographical correlation requirements (the “three pillars”) that broadly mirror but are not identical to the EU framework.
US Renewable Fuel Standard (RFS): applies to road and aviation transport, not yet maritime.
Japan, Korea, China, Singapore: each developing parallel frameworks with various degrees of alignment.

History of the EU RFNBO framework

The RFNBO concept was introduced in the 2018 Renewable Energy Directive (RED II, Directive (EU) 2018/2001) Article 27, but with limited operational detail. The detail was provided through:

Delegated Regulation 2023/1184 (adopted 10 February 2023, in force June 2023): the renewable electricity criteria.
Delegated Regulation 2023/1185 (adopted 10 February 2023, in force June 2023): the GHG savings methodology.

The two Delegated Acts were the result of a multi-year negotiation between the European Commission, the European Parliament and the Member States, culminating in a compromise that:

Defined additionality (the renewable installation must be new, i.e. commissioned within 36 months before the hydrogen plant first operates).
Permitted monthly matching during a transitional period (2024 to end of 2029) before mandatory hourly matching from January 2030.
Defined geographical correlation as same-bidding-zone (with limited exceptions for adjacent zones with adequate interconnection).
Set the 70% GHG savings threshold versus the fossil comparator (94 g-CO2eq/MJ for the EU electricity baseline in transport).

The RED III (Directive 2023/2413, in force November 2023) consolidated and strengthened the RFNBO framework, raising the 2030 transport target from 14% to 29% renewable energy share (with sub-targets including the 1% RFNBO marine sub-target).

Eligibility criteria

Additionality

The additionality criterion requires that the renewable electricity used to produce the RFNBO must come from a renewable installation that is new (commissioned no more than 36 months before the hydrogen plant first operates) and that does not benefit from operating aid (subsidies for ongoing operation, as distinct from investment aid for construction).

The intent of additionality is to ensure that RFNBO production drives net new renewable electricity generation, rather than diverting existing renewable generation away from the grid (where it would be replaced by fossil generation, leaving overall emissions unchanged).

The 36-month window is a compromise. A more restrictive window (e.g. 12 months) would require new renewable installations to be commissioned simultaneously with new hydrogen plants, which is operationally challenging. A more permissive window (e.g. 60 months) would allow significant pre-existing renewable installations to be reclassified as supporting RFNBO production.

Additionality is verified by the renewable electricity certificate (REC, GO, REGO depending on jurisdiction) bundled with a physical or virtual power purchase agreement (PPA) between the renewable installation owner and the RFNBO producer. The PPA must be at the wholesale price or higher (no subsidised pricing).

Exceptions to the additionality requirement:

Renewable installations in bidding zones with greater than 90% renewable electricity share (currently primarily Norway, Iceland, Sweden in some hours): additionality is presumed.
Renewable installations participating in the EU electricity market that have been operating for more than five years and that demonstrably do not displace other renewable demand: limited exception, subject to Member State approval.

Temporal correlation

The temporal correlation criterion requires that the renewable electricity must be matched to the hydrogen production within a defined time window:

Until 31 December 2029: monthly matching is permitted (the renewable electricity production in a given month must equal or exceed the hydrogen production electricity demand in the same month).
From 1 January 2030: hourly matching is required (the renewable electricity production in each hour must equal or exceed the hydrogen production electricity demand in the same hour).

The hourly matching requirement is significantly stricter than monthly matching. Modelled hydrogen production cost increases of 20 to 40% are anticipated when transitioning from monthly to hourly matching, principally because:

Solar PV and wind generation are intermittent; hourly matching requires the hydrogen plant to operate at variable load (typically 30 to 70% capacity factor) rather than the steady-state operation that would minimise capital cost.
Energy storage (batteries, pumped hydro) is needed to buffer the mismatch between renewable production hours and hydrogen production hours.
Multiple renewable installations (solar, onshore wind, offshore wind) are typically needed in a portfolio to achieve high temporal coverage.

The hourly matching transition has been challenged by hydrogen industry groups (Hydrogen Europe, several large utilities) arguing for monthly matching to be retained or for the hourly transition to be delayed. The European Commission has signalled intent to retain the hourly transition but is under continuing political pressure.

Geographical correlation

The geographical correlation criterion requires that the renewable electricity and the hydrogen plant must be in the same electricity bidding zone, or in adjacent bidding zones with adequate interconnection capacity to demonstrate physical electricity flow.

The intent is to prevent paper trading of renewable electricity across long distances where physical electricity flow is constrained (which would dilute the additionality argument by attributing renewable generation to consumption that is physically supplied by fossil generation).

Bidding zones are the wholesale electricity market areas defined under the EU electricity market regulation. Major EU bidding zones include: Germany-Luxembourg, France, Spain, Italy (multiple zones), Nordic (Norway, Sweden, Denmark, Finland: multiple zones), Benelux, Iberian, Eastern European zones. The renewable installation and the hydrogen plant must be in the same zone, or the producer must demonstrate physical electricity flow from the renewable zone to the hydrogen zone.

70% GHG savings

The 70% GHG savings criterion requires that the RFNBO must achieve at least 70% lower WtW intensity than the fossil comparator, calculated under the methodology of Delegated Regulation 2023/1185.

For marine fuel, the fossil comparator is 94.0 g-CO2eq/MJ (the average WtW intensity of marine fuel oil per the Joint Research Centre WtW analysis). The 70% threshold therefore corresponds to a maximum RFNBO WtW intensity of 28.2 g-CO2eq/MJ.

The 70% threshold applies to all eligible feedstocks and pathways. Renewable hydrogen produced from solar, wind, hydroelectric, geothermal, tidal, wave, ocean thermal energy conversion or sustainable biomass-electricity is eligible. Hydrogen produced from nuclear electricity is not classified as RFNBO under the EU framework (it is a separate category called low-carbon hydrogen (LCH), with its own framework).

The GHG savings calculation includes:

Renewable electricity production emissions: typically 5 to 25 g-CO2eq/kWh from manufacturing, transport and end-of-life of the renewable installation.
Electrolyser emissions: principally from electricity used in compression and water purification, plus stack manufacturing emissions.
Downstream synthesis emissions: for ammonia (Haber-Bosch process), methanol (from green hydrogen + CO2), or e-LNG (Sabatier process).
CO2 capture emissions: where the synthesis pathway uses captured CO2, the capture process emissions are included; the captured CO2 itself is generally counted as having an upstream emission of 0 (regardless of source) for the purposes of RED III, with the rationale that the CO2 would otherwise be emitted to the atmosphere.
Transport and bunkering emissions: the emissions from transporting the RFNBO from production to bunker and from bunker to vessel.

RFNBO marine pathways

Green hydrogen (H2)

Green hydrogen is produced by electrolysis of water using renewable electricity. The principal electrolyser technologies are:

Alkaline electrolysers (AEL): mature technology, low capex, moderate efficiency (typically 60 to 70% LHV); the dominant commercial technology.
Proton Exchange Membrane (PEM) electrolysers: higher capex, faster ramp rate, more compact; suitable for variable renewable electricity input.
Solid Oxide Electrolyser Cells (SOEC): high efficiency (potentially 80 to 90% LHV) but commercial maturity still limited.
Anion Exchange Membrane (AEM) electrolysers: emerging, lower capex than PEM.

Hydrogen is technically usable as a marine fuel (in fuel cells or in modified internal combustion engines), but the storage challenge is severe: liquid hydrogen requires cryogenic storage at -253 °C, and compressed gaseous hydrogen requires very high pressures (350 to 700 bar). Direct hydrogen fuel cell propulsion is being pioneered on small ferries (Norled MF Hydra, in service April 2023) but is not yet commercially attractive for larger vessels because of the storage volume penalty.

Most marine RFNBO is therefore in the form of derivatives, principally green ammonia and e-methanol.

Green ammonia (NH3)

Green ammonia is produced by reacting green hydrogen with nitrogen via the Haber-Bosch process. Ammonia is a more practical marine fuel than hydrogen because:

Energy density: ammonia liquefies at -33 °C at atmospheric pressure (or at moderate pressure, e.g. 8 to 10 bar at ambient temperature), with significantly less storage volume than liquid hydrogen.
Existing infrastructure: there is a substantial existing ammonia production, transport and storage infrastructure (ammonia is the second-most-traded chemical commodity globally, principally for fertiliser production).
Engine compatibility: ammonia dual-fuel engines (MAN Energy Solutions, Wartsila, Win GD) are commercially available from 2024 to 2027 timeframe.

The principal engineering challenge is N2O slip from ammonia engines (which has GWP of 265) and the ammonia toxicity (which requires careful handling, particularly during bunkering). See ammonia as marine fuel for a full treatment.

E-methanol

E-methanol is produced by reacting green hydrogen with captured CO2 via the methanol synthesis process. The CO2 can come from:

Biogenic sources: fermentation, anaerobic digestion, biomass combustion. Highest sustainability rating.
Industrial sources: cement, lime, steel, chemicals. Counts as utilisation of CO2 that would otherwise be emitted.
Direct air capture (DAC): extracted directly from atmospheric air. Most expensive but theoretically unlimited.

E-methanol is the marine RFNBO with the most extensive newbuild order book: as of end-2024, Maersk (24 newbuild methanol-fuelled container ships ordered, 5 in service), CMA CGM (15 newbuild methanol-fuelled container ships), MSC (8), OOCL (7), Cosco (12), Hapag-Lloyd (some retrofit options) and several other major lines have firm orders. The methanol bunker supply chain is being scaled to match: OCI Global, Equinor, Stena Bulk, Methanex, Proman, NextChem, Drax and several other producers have announced or are constructing e-methanol production capacity targeting marine demand. See methanol as marine fuel for a full treatment.

E-LNG (synthetic methane)

E-LNG is produced by reacting green hydrogen with captured CO2 via the Sabatier process (methanation). E-LNG is chemically identical to fossil LNG but with near-zero WtW intensity if produced under RFNBO criteria.

E-LNG is interesting for the substantial existing LNG dual-fuel fleet (approximately 1,000 vessels in operation by end-2024 plus a similar number on order), which can theoretically transition to e-LNG without engine modification. However, e-LNG production cost is significantly higher than e-methanol or green ammonia for the same carbon emissions reduction, principally because of the additional energy required for methanation. Commercial e-LNG production is at small pilot scale in 2024.

Other RFNBO pathways

Other RFNBO pathways under development include:

E-diesel (synthetic diesel from green hydrogen + CO2 via Fischer-Tropsch): directly compatible with existing diesel engines but at much higher cost than e-methanol.
E-DME (dimethyl ether): alternative to methanol with some operational advantages.
E-kerosene (synthetic aviation fuel): principally targeted at aviation but with potential marine applications.

Certification and verification

Voluntary certification schemes

Compliance with the RFNBO criteria must be verified by an EU-recognised voluntary certification scheme. The EU has recognised several schemes for RFNBO certification:

ISCC EU (International Sustainability and Carbon Certification, headquartered in Cologne, Germany): the dominant scheme, with substantially all major RFNBO-marine producers certified or in process.
REDcert (also based in Germany): an alternative EU-recognised scheme.
Better Biomass (Netherlands): focused on biomass feedstocks.
Roundtable on Sustainable Biomaterials (RSB): multi-feedstock, internationally recognised.
Bonsucro: sugar-cane specific, not directly applicable to RFNBO but used for related biofuel certification.

Each scheme operates under EU recognition, periodically reviewed by the European Commission. Producers and traders must maintain a chain-of-custody throughout the production, transport and bunkering chain to preserve the RFNBO classification.

Bunker delivery note (BDN) integration

Marine bunker delivery notes (BDNs) issued for RFNBO must include the certified WtW intensity, the RFNBO classification (i.e. compliance with the additionality, temporal, geographical and 70% GHG savings criteria), the certification scheme name and the unique batch identifier. The vessel uses the BDN to claim the FuelEU Maritime multiplier and the EU ETS zero-rating.

The BDN format for RFNBO is governed by MARPOL Annex VI Regulation 18 (BDN format) as amended for FuelEU compliance, with additional fields specified by the EU and by national flag states.

Notable developments and the RFNBO supply chain

EU Hydrogen Bank

The EU Hydrogen Bank is an auction-based support scheme for green hydrogen production, intended to bridge the cost gap between green hydrogen and fossil hydrogen. The first round (2023 to 2024) auctioned approximately EUR 800 million of support to seven projects with a combined annual production capacity of approximately 1.6 million t H2-equivalent. Subsequent rounds are planned annually.

The Hydrogen Bank prioritises projects supplying RFNBO-eligible hydrogen for transport (principally aviation, maritime and heavy-duty road) and for industrial use (steel, chemicals).

IPCEI Hydrogen and the European hydrogen valley initiative

The Important Project of Common European Interest (IPCEI) Hydrogen is an EU-coordinated state-aid framework that allows Member States to support large-scale hydrogen projects across the value chain, including production, transport, storage and use. By end-2024 IPCEI Hydrogen has supported approximately 80 projects with combined investment of approximately EUR 18 billion.

Repsol, OCI Global, Maersk methanol projects

The OCI Global e-methanol production facility at the Port of Rotterdam (in commissioning 2024 to 2025) is the principal European e-methanol supply project for marine, with capacity of approximately 200,000 t/y in phase 1.

The Repsol e-methanol facility at Bilbao (in development for delivery 2027 to 2028) is the principal Spanish project.

The Maersk-Equinor Sustainable e-Fuels for Shipping partnership announced in 2023 commits to multi-decade offtake of e-methanol from Equinor production facilities.

Topsoe SOEC ammonia

Topsoe (Denmark) is constructing a SOEC-based green ammonia production plant at Herning (in development for 2027 delivery), one of the first commercial-scale SOEC-based green ammonia plants.

Yara green ammonia

Yara (the largest ammonia producer in Europe) is converting parts of its existing Porsgrunn ammonia plant to green ammonia production using renewable hydrogen, with first commercial volumes expected from 2025 to 2026.

CF Industries blue ammonia

CF Industries (USA) and OCI Global are scaling blue ammonia production (from natural gas with CCS) as a transition fuel ahead of green ammonia scale-up. Blue ammonia does not qualify as RFNBO (because it is fossil-derived) but does have low WtW intensity (approximately 25 to 35 g-CO2eq/MJ) and qualifies for FuelEU Maritime compliance on the basis of the certified WtW intensity (without the RFNBO multiplier).

Singapore, Korea and Japan ammonia bunkering

The ports of Singapore, Busan (South Korea), Yokohama (Japan) and several others have announced commitments to develop ammonia bunkering infrastructure. The Singapore-Rotterdam Green and Digital Shipping Corridor is the principal early bilateral framework for cross-pacific RFNBO-ammonia trade.

Limitations and risks

Cost gap

RFNBO marine fuels are currently approximately 3 to 8 times more expensive than conventional fossil fuels on an energy-equivalent basis (EUR per GJ). The cost gap is expected to narrow over time as renewable electricity costs continue to fall, electrolyser costs decline and infrastructure scales, but a significant cost premium is expected to persist through the 2030s.

The FuelEU Maritime multiplier of 2x and the EU ETS zero-rating partially offset this cost premium for vessels with EU exposure. The IMO Net-Zero Framework Tier 1 / Tier 2 remedial unit pricing from 2027 will further offset the cost premium, although the offset is unlikely to fully close the gap before approximately 2035.

Hourly matching transition

The transition from monthly to hourly matching in January 2030 is the principal regulatory uncertainty for current RFNBO investment. Producers planning the transition must invest in either (a) on-site energy storage to buffer hourly mismatches, (b) a portfolio of renewable installations to provide hourly coverage, or (c) flexible electrolyser operation that can ramp with renewable production hour-by-hour. Each option adds cost.

Geographical correlation in lightly interconnected regions

For RFNBO production in regions with limited renewable resources locally (e.g. some northern European industrial centres), the geographical correlation requirement may force imports from far away (e.g. Iberia, Maghreb), with the cost of long-distance transport eroding the WtW intensity advantage. Some mitigation through hydrogen pipeline and shipping infrastructure is anticipated through the 2030s, but the constraint will continue to shape the geography of RFNBO production.

Competition from non-EU jurisdictions

The US Inflation Reduction Act Section 45V production tax credit for clean hydrogen (up to USD 3/kg H2 for the highest tier) is a more generous subsidy than the EU framework. The risk is that EU-targeted RFNBO production migrates to the US to capture the IRA subsidy, with the subsidised hydrogen then exported to the EU as e-methanol or e-ammonia. The EU framework’s strict additionality criteria may accommodate this if the US-side production also meets the EU criteria, but there is significant interpretive uncertainty.

Scope 3 carbon accounting

The captured CO2 used in e-methanol or e-LNG is treated as having upstream emission of 0 in the EU RFNBO framework, on the rationale that the CO2 would otherwise be emitted to the atmosphere. This treatment is contested by some carbon-accounting analysts who argue that the CO2 should bear the upstream emissions of its source process. The EU framework may evolve on this point over the 2030s.

Additionality erosion

If the additionality requirement is significantly relaxed (e.g. by extending the 36-month window to 60 months, or by allowing existing renewable installations to be reclassified for RFNBO support), the climate benefit of RFNBO is significantly diluted. Several EU Member States have lobbied for relaxation of the additionality criterion; the European Commission has so far resisted but is under continuing political pressure.

Implications for owners, charterers and insurers

Owners

Vessel owners specifying methanol or ammonia dual-fuel engines for newbuild orders face the question of bunker supply: in the near term (through approximately 2027), only fossil and blue methanol/ammonia will be available in commercial volumes; from approximately 2028 onwards RFNBO methanol and ammonia will become increasingly available. Owners may need to bridge with non-RFNBO bunkers in the early years, accepting the lower regulatory benefit while preserving optionality for RFNBO bunkering once available.

Charterers

Long-term charterers and parcel charterers (including container ship shippers and tanker charterers) increasingly require RFNBO bunker supply from the operating owner, often paying a premium for the certified RFNBO classification. The contract framework for this is evolving; the BIMCO clauses for FuelEU pass-through are the principal current model.

Insurers

Marine insurers are beginning to integrate RFNBO and WtW intensity into hull and P&I underwriting, particularly for Poseidon Principles signatories who must report annual portfolio WtW intensity. The expansion of insurance to cover ammonia bunkering operational risk is a significant ongoing development.

Banks and finance

Ship-finance banks are integrating RFNBO bunker supply commitments into loan covenants for newbuild orders, particularly for Poseidon Principles signatories. The pricing of green-shipping-corridor bonds and sustainability-linked loans is increasingly tied to certified RFNBO bunker supply.

References

Directive (EU) 2023/2413 of the European Parliament and of the Council of 18 October 2023 amending Directive (EU) 2018/2001 (RED III). Official Journal of the EU, 2023.
Commission Delegated Regulation (EU) 2023/1184 of 10 February 2023 supplementing Directive (EU) 2018/2001 by establishing a Union methodology setting out detailed rules for the production of renewable liquid and gaseous transport fuels of non-biological origin. Official Journal of the EU, 2023.
Commission Delegated Regulation (EU) 2023/1185 of 10 February 2023 supplementing Directive (EU) 2018/2001 by establishing a minimum threshold for greenhouse gas emissions savings of recycled carbon fuels and by specifying a methodology for assessing greenhouse gas emissions savings from renewable liquid and gaseous transport fuels of non-biological origin and from recycled carbon fuels. Official Journal of the EU, 2023.
Regulation (EU) 2023/1805 of the European Parliament and of the Council of 13 September 2023 on the use of renewable and low-carbon fuels in maritime transport (FuelEU Maritime). Official Journal of the EU, 2023.
Regulation (EU) 2023/959 of the European Parliament and of the Council of 10 May 2023 amending Directive 2003/87/EC (EU ETS Maritime). Official Journal of the EU, 2023.
IMO Resolution adopted MEPC 83 (April 2025): IMO Net-Zero Framework. International Maritime Organization, 2025.
European Commission. Hydrogen Bank: First Auction Results. CINEA, 2024.
DNV. Maritime Forecast to 2050. DNV Energy Transition Outlook, 2023.
Hydrogen Europe. RFNBO Market Outlook. Hydrogen Europe, 2024.
ICCT. The cost of zero-emission ships and shipping. International Council on Clean Transportation, 2022.