Japan Builds Its SAF Architecture: A Supply Mandate and a User Levy

Japan is assembling the demand side of its SAF policy in two pieces. METI's Task Force is designing a blending obligation on jet fuel suppliers. MLIT's expert council is designing a user-funded levy to pay down the price gap. Neither is law yet, but both are detailed enough to read seriously, and the logic connecting them is the point: one guarantees that SAF gets bought, the other makes buying it survivable for airlines competing on thin international margins.

Supply obligation: 1% in 2030, 5% by 2032

The obligation would fold jet fuel supply into the High-Degreeization Act as a "specified energy supply business," the same statutory hook that already sets petroleum refiners' bioethanol targets. Suppliers would have to blend a rising share of SAF into national jet fuel supply: 1% in FY2030, 3% in FY2031, and 5% from FY2032 through FY2034. That puts Japan at the cautious end of the international field. The EU starts at 2% and jumps to 6% in 2030; the UK runs a much steeper curve to 14.5% by 2034; Korea and Singapore are working toward non-binding 3–5% bands. Japan's stated rationale: start small, scale as social acceptance builds is pragmatic.

Scope is narrower than the percentage suggests. For the first notification period, 2030–34, the obligation covers only international flights, passenger and cargo, departing the seven airports that handle about 99% of Japan's international refuelling: Narita, Haneda, Kansai, Chubu, New Chitose, Fukuoka, and Naha. Domestic routes are carved out for this period, even though the statutory base for "domestic supply volume" nominally spans both. The TF materials treat this as sequencing, not exemption: domestic treatment gets revisited once ICAO's post-2035 scheme firms up.

Obligated parties are suppliers moving 3,000 kL/year or more through the covered airports, importers included, with an explicit block on splitting volume across sub-threshold group entities to duck the requirement. The more strategically loaded feature sits one level down: for large suppliers producing over 100,000 kL/year domestically, half of their SAF supply must be domestic SAF or SAF from overseas affiliates. That clause ties the mandate to energy security, not just decarbonisation - it's there to make sure the demand pull lands on Japanese production capacity rather than flowing straight to imports.

Compliance flexibility is real but deliberately narrow. Shortfalls can be banked forward through FY2033. Suppliers can also credit SAF delivered to non-CORSIA carriers, government and JSDF aircraft, USFJ aircraft, SAF exported for foreign-airport use, or SAF transferred to other domestic suppliers. What explicitly does not earn relief: equipment breakdown, failed commercial talks with airlines, or cost overruns delaying a plant's FID. That last exclusion is a signal to producers - the obligation pushes commercial risk back onto suppliers.

Why the timeline is tight

Three pressures are converging, and MLIT links them directly. CORSIA is already biting: 2024 emissions triggered roughly 55 Mt of reduction/offset obligation under the scheme's 85% baseline suppression, the 2025 ICAO Assembly adopted a 2030 SAF-use goal of 5% emissions-basis reduction, and post-2030 targets plus the post-2035 offsetting architecture are now in active negotiation. Domestic refining capacity is set to decline as broader decarbonisation proceeds, and because jet fuel is a co-product of gasoline refining, the Mizuho industrial research cited in the materials projects a widening jet fuel supply-demand gap to 2050 even as APAC aviation demand climbs. And disruption to Iranian oil-linked supply chains has sharpened the security case for domestic production, including strategic reserve costs.

Four projects have already cleared GX Transition Bond CAPEX support: Idemitsu (Yamaguchi/Chiba, HEFA/ATJ, 350,000 kL/year combined), ENEOS (Wakayama, HEFA, ~400,000 kL/year), Taiyo Oil (Okinawa, ATJ, 200,000 kL/year), and Cosmo Oil (Kagawa, ATJ, 150,000 kL/year). All are mid-design-phase, with FIDs expected within the year.

User levy: spreading the price gap across the network

The second piece, under deliberation at MLIT's Council of Experts on Sustainable Aviation Decarbonisation since April 2026, tackles who absorbs the wedge between SAF and jet fuel. That wedge has run 240–480 JPY/L over the past two to three years and spiked again on Iran-related disruption, against a jet price that has stayed comparatively flat.

MLIT's framing treats the "decarbonised aviation network" itself as the thing being paid for, with airlines, airports, and ultimately passengers and shippers as its beneficiaries. The concern is that airlines under international competitive pressure won't pass SAF costs through in fares on their own, leaving the network under-funded - a gap a public, distance-based levy on users departing the seven hubs is meant to close. The council's own diagram makes the mechanism plain: supply-side CAPEX and OPEX support pushes the supply curve down, the user levy pushes the demand curve up, and the two are meant to meet at a price the market will actually clear.

The passenger/cargo split is where the design is at the early stages. On comparable Tokyo–Europe surcharges, passenger SAF surcharges run around 20 JPY/kg equivalent against 7.3 JPY/kg for cargo, roughly triple per kilogram. Cargo also has no on-ticket collection point, which is why MLIT flags it as harder to design than the passenger side — notwithstanding that air cargo is just 0.7% of Japan's international freight tonnage by mode (against 99.3% for sea) yet carries nearly a third of international route weight measured against passengers. Who collects and administers the levy; airports, the state, or a designated body is unresolved, as is the 2035 expansion to non-hub airports and domestic routes, timed to track the next tightening of CORSIA and the Global Warming Countermeasures Plan.

What to watch

The obligation rides a High-Degreeization Act amendment and sits with METI. The levy is still at concept-and-consultation stage under MLIT's council, four sessions in as of mid-July 2026, with no published rate or collection mechanism. The two are built to reinforce each other - the obligation guarantees offtake, the levy funds the differential that makes offtake viable for airlines - but they move on separate tracks, and the collection mechanism plus the passenger/cargo and hub/non-hub scope questions are the variables that will decide landed SAF cost for Japanese carriers after 2030.