CORSIA Eligible Emissions Units (EEUs): What They Are

What separates a CORSIA Eligible Emissions Unit from an ordinary carbon credit, the two layers of eligibility assessment, why the eligible pool is so much smaller than the voluntary market, and how to tell the difference.

A CORSIA Eligible Emissions Unit (EEU) is a carbon credit that ICAO has determined may be used by aircraft operators to discharge their offsetting obligations. The definition matters because a great many carbon credits — including excellent ones — are not EEUs and never will be.

CORSIA eligible projects

The Definition

An EEU is a unit that:

Was issued by a crediting programme approved by the ICAO Council, and
Independently satisfies the ICAO Emissions Unit Criteria at unit level

Both halves are required. Neither stands alone.

"It's from Verra" or "it's from Gold Standard" is not an answer to "is it CORSIA eligible". Those programmes issue enormous volumes, and only a fraction of that supply meets the unit-level tests.

Two Layers of Assessment

Layer 1 — programme approval

The Technical Advisory Body (TAB) assesses crediting programmes against the Emissions Unit Criteria and recommends to the ICAO Council, which decides.

Assessment covers governance, methodology development, additionality requirements, quantification, permanence provisions, validation and verification oversight, registry infrastructure, double-counting safeguards and social and environmental safeguards.

Approval may be full or conditional, is time-bounded, and is reassessed. It has lapsed. See approved crediting programmes.

Layer 2 — unit-level compliance

Even from an approved programme, an individual unit must independently satisfy the criteria — most consequentially vintage and the corresponding adjustment.

An approved programme with thirty years of issuance history has issued a great deal that falls outside current vintage windows and carries no host-State authorisation. Those units are perfectly valid credits. They are not EEUs.

Why the Eligible Pool Is So Small

Three filters compound, and the third does most of the work.

Filter	Effect on the global credit pool
Must come from an ICAO-approved programme	Removes supply from unapproved standards
Must fall in an eligible vintage window	Removes most historical issuance
Must carry a host-State corresponding adjustment	Removes the large majority of what remains

The corresponding adjustment requirement means the government where the reduction happened must add those tonnes back into its own national accounting, forgoing them against its Paris Agreement target. Many governments decline for some or all project types. Others have no administrative process for it at all.

The result is a genuinely two-tier market. Eligible supply is scarce and trades at a substantial premium to comparable non-eligible supply from the same projects. See corresponding adjustments and Article 6.

EEU vs Voluntary Credit

	CORSIA EEU	Voluntary credit
Who sets the standard	ICAO, uniformly	The buyer, individually
Programme constraint	Must be ICAO-approved	Any standard the buyer accepts
Corresponding adjustment	Required	Usually absent
Vintage	Must be in an eligible window	Buyer preference only
What it buys	Regulatory discharge	A claim the buyer defines
Retirement	Cancellation designated for CORSIA	Retirement with a self-defined claim
Price	Substantial premium	Very wide range
Documentation	Must survive audit years later	Varies enormously

Every EEU could be sold voluntarily. Only a small minority of voluntary credits could be sold as EEUs.

Language That Signals a Unit Is Not Eligible

Three phrases recur in this market. All three describe units that are not currently eligible:

"CORSIA-ready" — not a standard. Usually means the project is registered under an approved programme with no authorisation.
"CORSIA-aligned" — not a standard either.
"Eligible pending authorisation" — at least honest about the gap. Authorisation is a sovereign decision with no guaranteed timeline.

Buying against any of these means taking authorisation risk. That can be a deliberate, priced decision — forward contracts often work exactly this way — but it should be deliberate, and the contract should allocate the risk explicitly.

How to Verify a Unit Is an EEU

A short sequence, expanded in the emissions unit criteria:

Is the issuing programme currently ICAO-approved? Check at the point of transaction, not from a saved list.
Is the approval full or conditional, and does any condition touch these units?
Is the vintage inside the window for your compliance period?
Is there a host-State authorisation document naming these specific units?
Is there evidence the corresponding adjustment has been or will be applied?
Is the verification report from an accredited body, and does it carry qualifications?
Does the registry record show a clean, unbroken chain of custody?
Can you assemble all of this into a package that survives audit in three years?

Seller assurance is not evidence for any of these. Documents are.

Units and Tonnes

One EEU represents one tonne of CO2 equivalent reduced or removed.

Cancelling one EEU discharges one tonne of offsetting obligation. There is no discounting, multiplier or quality adjustment applied at the point of cancellation — a unit either qualifies fully or does not qualify at all.

That binary character is why due diligence matters so much. A unit that fails eligibility after cancellation does not merely waste the purchase price; it leaves an unmet obligation at the worst possible moment.

Where to Go Next

The emissions unit criteria — every requirement in detail
Approved crediting programmes — layer 1
Corresponding adjustments — the binding constraint
Vintages and eligibility windows — the timing constraint
Registries and cancellation — how units move

The authoritative list of approved programmes and eligible units is published on the ICAO CORSIA emissions units page.

DSTechnoverse conducts pre-transaction due diligence on EEUs for operators. Talk to our carbon markets team or apply as a CORSIA buyer or seller.