There is a peculiarity at the heart of the durable carbon-removal market: nearly everything worth buying has not been made yet. The plants are being built, the methodologies are settling, and the tonnes that a corporate buyer will retire in 2028 are being contracted now, by people signing for something they cannot inspect.
Two structures do almost all of that work. They get used interchangeably in conversation, and they should not be, because they allocate risk in opposite directions.
Forward offtake: you commit, you pay on delivery
An offtake agreement reserves volume and fixes a price today, with payment falling due as each delivery is certified. You have committed; you have not yet paid.
What it fixes is price and access. In a market where durable supply is scarce and compliance demand is tightening, the scarce thing is not the money — it is the tonnes, and specifically the tonnes from suppliers whose evidence will still look good in five years. An offtake gets you into that queue.
What it exposes you to is schedule. If the plant is late, your tonnes are late, and the hole appears in your reporting year rather than in your bank account. Your remedy lives entirely in the contract: replacement tonnes, a refund backstop, or nothing at all, depending on what you negotiated.
Prepurchase: you pay now, they build
A prepurchase pays a portion of the value upfront against tonnes that will be certified later. It is the instrument that has financed most of the first generation of engineered removal, for the simple reason that a plant cannot be built with a promise.
What it buys you is better than price: it buys priority. First call on first-site volume, the strongest terms a supplier can offer, and — for a buyer who cares about this — a genuine claim to have caused the capacity to exist, rather than merely to have bought from it.
What it exposes you to is counterparty risk. You are no longer a customer waiting for a delivery; you are a creditor with an unsecured claim on a company that is spending your money on steel. If the supplier fails, the tonnes do not arrive and neither does the cash. This is not an argument against prepurchase. It is an argument for doing it with your eyes open, and for asking harder questions about the balance sheet than you would if you were paying on delivery.
Fig. 1 — The same tonne, bought two ways
| Forward offtake | Prepurchase | |
|---|---|---|
| You pay | On each certified delivery | A portion upfront |
| Your main risk | Schedule — the tonnes are late | Counterparty — the supplier fails |
| Priority on scarce volume | Reserved | First call |
| Effect on supply | Signals demand | Builds the capacity |
| Suits a buyer who | Has a hard budget cycle and cannot pre-spend | Wants to shape supply and can carry the risk |
The question that matters more than the structure
Both instruments are promises about the future, which means the credit-worthiness of the promise is the whole product. Before you decide between them, decide whether the supplier's answer to "and if you are wrong?" is one you can live with.
Three things separate a real answer from a comfortable one. First, whether the supplier contracts conservative volumes — a producer selling every tonne it hopes to make has no margin for the batch that fails its laboratory test, and you will discover that at the same moment they do. Second, whether there is a replacement mechanism written down: make-good tonnes from later production, ahead of any refund, with the refund as a backstop rather than a hope. Third, whether you will see the evidence accumulate — batch records, laboratory results, the audit pack — or receive a certificate at the end and nothing before it.
That last one is the tell. A supplier who shows you the evidence trail as it is created is a supplier who cannot quietly discover a problem in year three. A supplier who shows you nothing until issuance is asking you to trust that no problem will arise — and, worse, has designed a process in which they would find out late too.
We publish our own answers to these questions on the buyers page, including the uncomfortable ones. It seemed inconsistent to write a diligence guide and then decline to be measured by it.
Common questions
Is a prepurchase just an offtake with worse cash flow?
No — it is a different instrument with a different risk. An offtake exposes you to schedule: if delivery slips, you have not paid, and your exposure is the tonnes you have not received. A prepurchase exposes you to counterparty: you have paid, and if the supplier fails you are a creditor rather than a customer. You accept that risk in exchange for priority, price and the fact that your money is what builds the capacity. The right question is not which is cheaper; it is which risk you are equipped to carry.
What protects me if the supplier misses the delivery date?
The contract, and nothing else — which is why the delivery terms matter more than the price. Look for three things: a replacement mechanism that schedules make-good tonnes from later production, a refund backstop if delivery fails entirely, and conservative contracted volumes so the supplier is not selling every tonne it hopes to make. A supplier who will not put a remedy in writing is telling you something.
Should I wait until there are certified tonnes on the market to buy?
You can, and you will pay for the privilege. Durable removal supply takes years to build and is being contracted years ahead; buyers who wait for a liquid spot market will find that the best-verified supply was committed long before it existed. The real argument for buying early is not price speculation — it is that early buyers shape how suppliers are held to account, and get first call on the volume that turns out to be good.
