Every port operator watching European maritime decarbonisation has been trained to look at the ship. FuelEU Maritime sets a vessel’s greenhouse gas intensity ceiling. EU ETS prices the carbon it emits. Both land on the ship owner or operator, and both are genuinely EU-wide.
A quieter mechanism has now been tested twice, and it does not touch the ship at all. It regulates the company that fuels the barge. The Netherlands ran this experiment first, from January 2026. Spain has just followed, with Royal Decree 611/2026. Nine months of Dutch market data now exist, and they suggest this lever is at least as commercially disruptive as the ones everyone has been tracking. For a port operator anywhere outside the EU, that data is worth reading now, not after a similar decree lands in your own jurisdiction.
Two different levers, easy to conflate
RED III, the EU’s recast Renewable Energy Directive, sets an economy-wide renewable transport target and leaves member states to transpose it nationally. Most of the transport chapter is about road fuel. But a handful of states have used their transposition to add a maritime-specific supply-side obligation: a binding requirement on the companies that sell bunker fuel, not the ships that buy it, to cut the greenhouse gas intensity of what they sell, with a rising sub-target for genuinely renewable fuel.
This is structurally different from FuelEU Maritime and EU ETS. Those sit on the vessel. A national supply-side mandate sits underneath them, on the fuel itself, before it reaches the ship. A ship calling at a port with no such mandate is still bound by the EU-wide vessel-side rules. The national layer affects the port’s competitiveness and its suppliers’ costs.
The Netherlands: the experiment nobody else has repeated yet
The Netherlands used its transposition to require marine fuel suppliers to cut the greenhouse gas intensity of fuel sold in Dutch waters by 2.9% in 2026, enforced through a tradable compliance certificate scheme. It took effect on 1 January 2026, making Rotterdam, Europe’s largest bunker hub, the first port anywhere to carry this cost.
The market response was immediate and measurable. Rotterdam’s bunker sales fell by 648,399 tonnes in the first quarter of 2026, their lowest level since 2009, while Antwerp-Bruges gained 662,506 tonnes over the same period, according to S&P Global Commodity Insights. By September, the compliance cost had pushed Rotterdam’s price premium over Antwerp to $20-25 per tonne, a five-month high, and the gap was still widening: compliance certificate prices rose more than 137% between late July and early September alone.
Crucially, the volume did not stay in the EU’s low-carbon column. It moved to Antwerp and Hamburg, both of which lack an equivalent supply-side obligation, because Belgium has delayed its own transposition (possibly to 2027, unconfirmed) and Germany has so far chosen not to impose one on maritime fuel at all. One bunker trader was quoted describing the effect plainly: the Dutch rule is “scaring a lot of people away,” particularly from the higher-sulphur grades most exposed to the compliance cost.
The lesson is not that supply-side mandates fail. It is that a mandate imposed unilaterally, ahead of its neighbours, buys emissions reductions on paper while handing volume, and quite possibly total emissions, to the port next door. That is a carbon leakage problem, and it shows up in trade statistics months before anyone updates an emissions inventory.
Spain: a second data point, deliberately narrower in scope
Royal Decree 611/2026, published in Spain’s Boletín Oficial del Estado and later confirmed in force by RDL 21/2026, sets Spain’s transposition of RED III’s transport decarbonisation targets through 2040. Its maritime chapter obliges fuel suppliers (petroleum, LPG and gas marketers, plus certain direct consumers) supplying fuel for domestic cabotage shipping to meet a rising greenhouse gas intensity reduction curve: 6.5% in 2027, 9% in 2030, 17% in 2035 and 33% in 2040. Nested inside that curve is a renewable-fuel sub-target rising from 2% to 20% over the same period, with only a thin allowance (0.2 percentage points in 2027) for flexibility toward the road fuel pool.
Two design choices distinguish Spain’s approach from the Dutch one. First, the obligation falls on suppliers, not vessel operators, exactly as in the Netherlands. However, it is scoped to domestic cabotage rather than all bunker fuel sold in Spanish ports, which should narrow (though not eliminate) the kind of cross-border leakage Rotterdam experienced. Second, the decree requires Spanish ports themselves to collect and report annual data on the fuel and electricity they supply, categorised by whether it is renewable, low-carbon, recycled-carbon or fossil. Ports are being written into the compliance chain as data providers, not just as the location where compliance happens.
Substantive obligations take effect from 31 December 2026, with the framework governing fully from 2027, as originally planned; the amending RDL published in August confirmed that timeline rather than changing it. The implementing SICCRE Order, which will set out certification details, remains a document worth tracking as it moves through consultation.
The market is not waiting to find out how this settles. Peninsula and Evos signed a memorandum of understanding in August 2026 to build up to 60,000 m³ of dedicated biofuel storage at Evos’ terminal in the Port of Algeciras, citing FuelEU Maritime and EU ETS as the immediate drivers. Guaranteed renewable bunker capacity in Spanish ports has shifted from projection to infrastructure commitment before the supply obligation has even taken full effect.
Not every “fuel supply rule” is doing the same job
It is worth being precise about what counts as a supply-side decarbonisation mandate, because the language is used loosely. Singapore’s Maritime and Port Authority regulates how much biofuel a licensed bunker tanker may carry, recently raising the limit to blends of up to B30. That is a blend ratio and safety standard governing how biofuel is physically handled and delivered. It is not a binding requirement on suppliers to cut the carbon intensity of what they sell, and it carries no equivalent to the Dutch or Spanish compliance curve. Conflating the two would overstate how far this regulatory model has actually travelled outside the EU. At present, the binding supply-side GHG mandate is a two-country experiment, both in the EU, both built on the same RED III transposition mechanism, with the rest of the bloc still watching Rotterdam’s numbers before deciding whether to copy it.
Why this is also a live test for the IMO’s Net-Zero Framework
The EU’s national patchwork is not unfolding in a vacuum. It is happening at the same time the International Maritime Organization is trying, and so far failing, to agree on the single global mechanism that was specifically designed to prevent this kind of fragmentation.
The IMO’s Net-Zero Framework, approved in principle at MEPC 83 in April 2025, pairs a global greenhouse gas fuel intensity standard with a pricing and reward mechanism, the first mandatory, economy-wide carbon price proposed for an entire industry sector.
It was due for formal adoption at an extraordinary MEPC session in October 2025. That session adjourned without adoption: a narrow majority of member states, 57 to 49, voted to delay a decision by a year rather than proceed, following sustained opposition led by the United States.
The process now comes to a head this winter: an intersessional working group (ISWG-GHG 23) meets on 23-27 November 2026, immediately followed by MEPC 85 and the resumed extraordinary session from 30 November to 4 December 2026, where the adoption vote is expected to be revisited. Based on typical MARPOL tacit-acceptance timelines, the earliest realistic entry into force has slipped into 2028.
There are signs of movement. A working group session in September 2026 showed a majority of member states that spoke, 38 against 17, backing some form of centralised revenue-and-reward mechanism, with the chair noting “genuine willingness” among delegations to reach final agreement by year-end. Opposition, led by the United States and joined by Saudi Arabia and other oil-producing states, continues to focus on the design of carbon pricing and revenue distribution rather than on the fuel-intensity standard itself.
The connection to Rotterdam is direct, not rhetorical. The entire argument for a global framework, rather than a patchwork of national and regional ones, is that it removes the incentive to relocate rather than reduce emissions. The EU has just demonstrated, at a regional scale and with real trade data, exactly what happens when that logic fails: one jurisdiction moves first, its neighbours do not follow on the same timetable, and the market answers with tonnes, not with emissions cuts.
A global framework that ends up adopted with carve-outs, phased coverage, or materially different national enforcement dates risks reproducing the Rotterdam-Antwerp-Hamburg pattern on a much larger map, between flag states and trading blocs rather than between neighbouring ports.
That is the argument industry bodies and member states supporting the Net-Zero Framework should be making as talks reach their decisive point at MEPC 85 and the resumed extraordinary session in late November and early December 2026: not only that a global carbon price is fairer or more ambitious than a patchwork of national ones, but that the EU’s own supply-side experiment is already showing what an uncoordinated alternative costs, in trade volume and market distortion, for limited demonstrated emissions benefit. Fragmentation is not a hypothetical risk to be weighed against sovereignty concerns at MEPC. It is a live case study, with a monthly bunker statistics update attached.
What this means for a port operator anywhere
Four things are worth tracking regardless of where a port sits:
- The regulatory layer that matters most may not be the one aimed at your customers’ ships. FuelEU Maritime and EU ETS get the attention because they are EU-wide and vessel-facing. The layer that moved 650,000 tonnes of bunker volume in a single quarter targeted the supplier, not the ship, and existed in only one country.
- Fragmentation is the risk, not the policy itself. Both the Dutch and Spanish mandates are reasonable attempts to secure the fuel supply chain FuelEU Maritime will eventually require. The damage in Rotterdam’s case came from being first and alone. A port whose neighbouring jurisdictions are transposing RED III on a different timetable, or not at all, is exposed to the same arbitrage even if it never adopts a mandate of its own.
- Watch late November, not just your own coastline. An intersessional working group meets on 23-27 November 2026, followed immediately by MEPC 85 and the resumed extraordinary session from 30 November to 4 December, where the Net-Zero Framework’s adoption is expected to be decided one way or another. Either outcome changes where fragmentation risk sits next, and for how long.
- Visibility now beats reconciliation later. The Rotterdam-Antwerp-Hamburg volume shift was visible in trade data well before it would have shown up in anyone’s Scope 3 or port-emissions reporting. A port or operator with real-time visibility into bunker volumes, supplier jurisdictions and compliance cost differentials can see a leakage pattern forming rather than explaining it after the fact. That is precisely the gap PortXchange’s EmissionInsider and Emission Reporter products are built to close for clients tracking port and maritime emissions exposure across multiple jurisdictions.
Spain will not be the last country to legislate this layer, and the IMO will not get a second chance to make the case for one global mechanism instead of many national ones. Both are worth watching over the next twelve months and beneath the different institutions, they’re the same story.
If you want to see what that exposure looks like for your own port, contact us for a live demo of EmissionInsider. Interested in reporting only? Grab a free sample of the Port Emissions Report.
