Covered by Schedule 16
The single code 2804 10, hydrogen, is listed under hydrogen in the Table in Schedule 16, and section 149(4) makes it a CBAM sector of its own with its own sectoral domestic price each quarter.
Outside the tax
No other code in heading 2804 is in the Table. A business that imports oxygen, nitrogen, argon or helium is outside the tax; the same business is inside it the day a tube trailer of hydrogen crosses the border under 2804 10.
Your business imports hydrogen in cylinders or tube trailers for an industrial gas depot, for a glass or metals plant that needs a reducing atmosphere, for a food plant that hydrogenates oils, for a refinery or chemical works, or for a fleet of fuel cell vehicles. Hydrogen is the smallest sector of the five by number of entries, and it is the sector in which the document's list of production routes leaves the most for the notice, in draft at the date of writing, to settle.
The system boundary
Table 1d of the System Boundaries Document maps 2804 10 00 to the category hydrogen, with carbon dioxide as the only relevant gas. Point 3.12.1 sets the boundary by three routes. For steam reforming and partial oxidation, monitoring covers all processes linked to hydrogen production and the separation of hydrogen and carbon monoxide, flue gas cleaning, and all fuels used in the process irrespective of their energetic or non-energetic use. For steam cracking, monitoring covers the processes linked to hydrogen production and to the production processes. For all three routes there are no precursors, so the supplier's figure is the supplier's own plant and nothing more.
The words about fuels matter. In steam reforming the natural gas is both the fuel that heats the reformer and the feedstock whose carbon leaves as carbon dioxide, and the document counts both. A producer who reports only the combustion emissions and leaves out the carbon in the feedstock has reported a fraction of the boundary. For by-product hydrogen from a cracker, the plant's emissions have to be divided between hydrogen and everything else the cracker makes, and the document refers the method of attribution to the emissions and verification notice, which exists only in draft.
The route the document does not name is electrolysis. The document counts direct emissions only, and HM Treasury's factsheet, which is guidance, states that the inclusion of indirect emissions within scope will be delayed until 2029 at the earliest. An electrolyser running on grid or contracted electricity has few direct emissions within that definition, and hydrogen made that way is still a covered good under 2804 10. How a verifier monitors an installation whose route the document does not describe is not stated in any instrument read for this site, and as at 13 September 2026 neither the draft notice nor any published default value dealt with it. An importer of electrolytic hydrogen should not assume that a low intensity will be available to it.
Weight is the figure to watch
Hydrogen weighs little and the tax is charged by the tonne of embodied emissions, which regulations 4 and 5 of SI 2026/995 derive from the weight of the good. Regulation 4 of SI 2026/802 fixes that weight as the net weight excluding packing materials and packing containers of any kind, at the time of import. For compressed hydrogen the cylinders, the tube trailer and the frame are packing containers, and the weight declared is the weight of the gas alone; for liquid hydrogen the tank and its insulation are excluded in the same way. A customs entry that carries the gross weight of a loaded trailer overstates the tonnage many times over.
The registration test is a value test, and for hydrogen the two diverge: a business importing hydrogen alone will cross £50,000 of customs value at a tonnage a steel importer would regard as trivial. Carbon price relief applies where the installation sits in a jurisdiction with a qualifying scheme under regulation 6 of SI 2026/809 and form CarbonVP1 can be obtained; because hydrogen has no precursors, one form covers the good.
Questions for a hydrogen supplier
Which production route is used, of the three the document names, or none of them. For a reformer or a partial oxidation unit: does the reported intensity include the carbon in the feedstock as well as the combustion of fuels. For a cracker: how are the plant's emissions attributed to the hydrogen stream, and has the verifier accepted the attribution. For an electrolyser: what intensity has the verifier reported and on what basis. For every supplier: is the weight on the commercial documents the net weight of gas, so that the customs entry can be reconciled to it. For every supplier in a jurisdiction with a carbon price: can form CarbonVP1 be completed for the installation.
The check to run
Take the twelve months of customs declarations for goods under heading 2804, sort them by eight-digit code, and set aside every line that is not 2804 10 00. For the lines that remain, confirm that the declared weight is the net weight of the gas, add the customs values to see whether the £50,000 threshold is in reach, and set against each line the production route of the installation that made the gas. Chapter 27 of UK CBAM for Importers sets out the sector in full.