Article 6.4's Methodology Pipeline Moves

At a glance

The consultation

What was on the table

The UNFCCC's Article 6.4 mechanism ran a public call for comments until 14 September 2026 on proposed methodology A6.4-PMM010, covering the partial substitution of fossil fuels with municipal solid waste in cement manufacture. The window opened on 24 August, and input was submitted on form A6.4-FORM-METH-007.

Cement is a useful test case for the mechanism. It is a hard-to-abate sector where the abatement lever is fuel substitution rather than process change, the counterfactual is a well-documented fossil baseline, and the feedstock — municipal solid waste — carries its own disposal emissions that a credible methodology has to account for on both sides of the boundary. How A6.4-PMM010 draws that boundary will set a precedent for waste-derived fuel crediting generally.

Methodological Expert Panel

The wider methodology pipeline

Running alongside the consultation, the mechanism's Methodological Expert Panel is reported to have met in Bonn from 7 to 11 September for its 16th session. The agenda covered new clean-cooking methodologies, a methodological tool for assessing reversal risk, sectoral methodologies for low-carbon ammonia production and renewable fertilisers, the calculation of electricity-related emissions, and revisions to sampling and survey standards and to Programme of Activities procedures.

If the agenda is accurate, the reversal-risk tool is the item with the widest consequence. It is the gating requirement for any removal activity seeking Article 6.4 registration: until a tool exists for assessing reversal risk, durability cannot be assessed under the mechanism at all, and removals cannot be credited on a comparable basis to reductions.

Supply side

What this means for sellers

Each named methodology is a defined pipeline. Cement substitution, clean cooking, low-carbon ammonia and renewable fertilisers are now categories a developer can design a project against with some confidence that a crediting route will exist. That is materially different from the position twelve months ago, when the Article 6.4 pipeline was a queue with no visible ordering.

For developers holding CDM-transition assets, the practical risk is that the mechanism finalises the rules governing their activity type before they have engaged with the drafts. Participation in a comment window costs a submission; retrofitting a project to a methodology written without your input costs considerably more.

Demand side

What this means for buyers

A consultation is a live influence point rather than a spectator event. A methodology that lands with weak baselines is one a procurement team will spend the next decade screening out — and the screening happens at the buyer's cost, project by project, long after the methodology is fixed.

The more strategic reading is that the Article 6.4 supply pool is being defined right now, in these documents. Buyers building a long-dated compliance position — CORSIA-eligible supply in particular, where host-country authorisation is already the binding constraint — should be reading the methodology pipeline as a forward supply curve, not as technical housekeeping.

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