Emission Allowance (EUA / UKA) — Definition and GHG Accounting Context
A carbon credit and an emission allowance both stand for one tonne of CO₂ and both trade for a price. It is tempting to treat them as the same thing. They are almost opposites.
A credit says a tonne was saved somewhere; an allowance says you are permitted to emit one — and confusing the two is one of the most common errors in carbon markets.
An emission allowance is a tradable permit, issued by a government under a cap-and-trade scheme, that entitles the holder to emit one tonne of CO₂e. Covered companies must surrender allowances equal to their verified emissions. The EU ETS issues EU Allowances (EUAs); the UK ETS issues UK Allowances (UKAs).
Emission allowances are the currency of compliance carbon markets. Where a carbon credit is a voluntary claim that a tonne was avoided or removed, an allowance is a mandatory permit to emit one — created by a regulator, capped in total, and surrendered against real emissions.
What an emission allowance is
An emission allowance is a tradable unit, issued by a government under an emissions trading scheme (a cap-and-trade system), that grants the right to emit one tonne of carbon dioxide equivalent. Every installation covered by the scheme must, each year, hold and surrender one allowance for every tonne it emits, as independently verified. The total number of allowances in circulation is fixed by the scheme’s cap — so allowances are, in effect, rationed permission to pollute.
Emission allowance — a government-issued, tradable permit authorising the emission of one tonne of CO₂e, created under a cap-and-trade emissions trading scheme. The number issued is limited by a declining cap; covered entities must surrender allowances equal to their verified emissions or face penalties. The EU ETS allowance is the EUA; the UK ETS allowance is the UKA.
Because the cap sets the supply and the market sets the price, an allowance carries a single, market-wide value at any moment — the “carbon price” that policymakers and companies watch. It is a compliance instrument first and a traded asset second.
Allowance vs carbon credit
This is the distinction that matters most. An allowance and a carbon credit both represent one tonne of CO₂e, but they are created differently, mean different things, and are not interchangeable:
| Feature | Emission allowance (EUA / UKA) | Carbon credit |
|---|---|---|
| What it is | A permit to emit, under a cap | A reduction or removal achieved elsewhere |
| It says | “You may emit one tonne” | “One tonne was avoided or removed” |
| Created by | A government / regulator | An independent crediting programme |
| Market | Compliance — mandatory | Mostly voluntary |
| Supply | Fixed by the declining cap | Depends on projects |
| Price | A single market-clearing price | Wide range, by project and quality |
| Examples | EUA, UKA, California CCA, RGGI | Verra VCS, Gold Standard credits |
In short, an allowance is created by capping emissions; a credit is created by reducing them. A company cannot generally meet an ETS obligation with a voluntary credit, and a voluntary offsetting claim cannot be substantiated with an allowance.
Where allowances come from
The regulator first sets a cap — the total tonnes the covered sectors may emit — and issues exactly that many allowances. The cap declines every year (in the EU ETS, by a fixed linear reduction factor), tightening supply and, all else equal, raising the price over time. Allowances reach the market two ways:
| Route | How it works |
|---|---|
| Auctioning | The majority of allowances are sold at auction; companies buy what they need. Auction revenue goes to governments. |
| Free allocation | Some allowances are given free to sectors exposed to carbon leakage, allocated by product benchmarks. This is being phased down as the carbon border adjustment mechanism is phased in. |
The compliance cycle
Each covered installation runs an annual cycle: it monitors emissions, has them verified, and by the compliance deadline surrenders one allowance per verified tonne. From there the market does its work:
- Shortfall — an installation emitting more than its allowances must buy the difference on the market or at auction.
- Surplus — an installation that cut emissions can sell its spare allowances, or bank them for future years. This is the incentive to abate: every tonne avoided is an allowance freed to sell.
- Stability mechanisms — schemes such as the EU ETS use a Market Stability Reserve to absorb surplus allowances and steady the price.
Banking allowances forward is generally allowed; borrowing from future years generally is not. The surrender obligation, backed by penalties well above the allowance price, is what gives the whole system teeth.
EUAs, UKAs and other allowances
| Allowance | Scheme |
|---|---|
| EUA — EU Allowance | The EU Emissions Trading System, the world’s largest carbon market, covering power, heavy industry, aviation and shipping. |
| UKA — UK Allowance | The UK Emissions Trading Scheme, the standalone system established after the UK left the EU ETS. |
| CCA, RGGI, others | California and Quebec allowances, the US Regional Greenhouse Gas Initiative, China’s national ETS and more. |
EUAs and UKAs are separate instruments in separate markets — since the UK left the EU ETS they are no longer linked, and their prices diverge. An EUA cannot be surrendered under the UK ETS, nor a UKA under the EU ETS.
Common mistakes
- Confusing an allowance with a carbon credit. An allowance is a permit to emit under a cap; a credit is a reduction achieved elsewhere. They are different instruments and rarely interchangeable.
- Thinking free allocation means free to emit. Free allowances still have to be surrendered against emissions — they cut a company’s cost, not its obligation.
- Using an allowance as a voluntary offset. Cancelling an allowance removes it from the market, but it is not a project-based offset and does not substantiate a credit-style neutrality claim.
- Treating EUAs and UKAs as the same. They belong to separate, unlinked schemes with separate prices and are not fungible.
- Ignoring the declining cap. The number of allowances shrinks every year by design, so today’s supply and price are not a guide to the future.
A carbon credit says a tonne was saved somewhere; an emission allowance says you are allowed to emit one. They are opposite instruments that happen to share a unit.
Work out an allowance obligation or a carbon-price exposure.
An emission allowance is a tradable permit, issued by a government under a cap-and-trade emissions trading scheme, that authorises the holder to emit one tonne of CO₂e. Companies covered by the scheme must surrender one allowance for every tonne they emit. The EU ETS issues EU Allowances (EUAs) and the UK ETS issues UK Allowances (UKAs).
An emission allowance is a permit to emit one tonne, created by a regulator under a cap and used for mandatory compliance. A carbon credit represents a tonne avoided or removed by a project elsewhere, created by an independent programme and used mostly for voluntary claims. An allowance is made by capping emissions; a credit is made by reducing them — and the two are generally not interchangeable.
EUA stands for EU Allowance, the unit of the EU Emissions Trading System — the world’s largest carbon market. UKA stands for UK Allowance, the unit of the UK Emissions Trading Scheme, established after the UK left the EU ETS. Each is a permit to emit one tonne of CO₂e within its own scheme, and the two are not fungible.
Mostly by buying them — the majority of allowances are sold at government auctions, and companies also trade them on the secondary market. A portion is handed out free to industries at risk of carbon leakage, allocated according to product benchmarks, though free allocation is being reduced as border carbon adjustment measures take effect.
Not in the way a carbon credit works. Allowances are compliance permits, not project-based reductions. Buying and cancelling an allowance does tighten the market by removing a permit to emit, which some treat as a form of climate action, but it is not an offset in the credit sense and does not substantiate a carbon-neutrality claim.