An offtake agreement is a contract in which a buyer (the offtaker) commits in advance to purchase the output, capacity, or services of a project over a defined term. The agreement exists primarily to convert a project's expected production into a contracted, bankable revenue stream: lenders and equity investors will finance a plant far more readily when a creditworthy counterparty has agreed to take its output for years rather than leaving the project exposed to the spot market alone. In the energy-storage context, the offtaker is usually paying for the right to charge, discharge, and dispatch a battery system, and the agreement sets the term, the pricing mechanism, and the obligations of each side.

The structure is not theoretical; it appears in SEC filings as a stated fact about a project's revenue arrangements. In its Form 10-K filed with the U.S. Securities and Exchange Commission, Energy Vault Holdings, Inc. describes the offtake behind its Cross Trails Battery Energy Storage System in Scurry County, Texas. The filing states that the company signed a 10-year offtake agreement with a power marketer and that, when completed, the project is designed to provide 57 MW of power with a 2-hour battery capacity, serving the ERCOT Day-Ahead market.

"We began construction on Cross Trails in 2024 and also signed a 10-year offtake agreement with Gridmatic, a leading AI-enabled power marketer."— SEC, Energy Vault Holdings Form 10-K, source

What the term length and counterparty tell you

Two attributes of an offtake agreement carry most of the financial weight: the term and the counterparty. The term — here, ten years — sets how long the project's revenue is contracted rather than merchant. A longer term shifts price risk away from the project owner and toward the offtaker, which is why financiers treat a multi-year offtake as a precondition for project debt. The counterparty's identity matters because the contract is only as good as the buyer's ability to pay over that horizon; in the Energy Vault disclosure the offtaker is described as a power marketer that resells the dispatched energy and capacity into the ERCOT wholesale market. The filing also specifies the technical envelope the offtake is written against — 57 MW of power and 2-hour duration — because an offtaker is buying a defined quantity of dischargeable energy, not an open-ended promise.

It is worth distinguishing an offtake agreement from the related contract types that appear in the same filings. A power purchase agreement (PPA) is one form of offtake in which the buyer purchases the electricity a project produces. A tolling agreement is another: the customer pays for the right to dispatch the storage asset and to keep the resulting energy, while the project owner retains ownership of the hardware. Energy Vault's filings describe both ownership models — selling systems outright and, in certain cases, retaining ownership and entering tolling arrangements. "Offtake agreement" is the umbrella term for the long-term purchase commitment; PPAs and tolling structures are specific shapes that commitment can take.

Why the offtake is the revenue spine of a storage project

For a standalone battery, revenue can come from several stacked sources — energy arbitrage, capacity payments, and ancillary services such as frequency regulation. Each of those is volatile and market-dependent. An offtake agreement is the instrument that smooths that volatility into something a lender can underwrite: a contracted floor or fixed payment in exchange for the offtaker's right to the asset's output. That is why, in the Energy Vault disclosure, the offtake is mentioned in the same breath as the start of construction. The contracted revenue is what makes the build financeable, and the filing presents the two events together because, in project economics, they are linked.

Readers parsing a storage filing for the strength of an offtake should look for the term, the named counterparty, the contracted capacity and duration, and the market the output serves — all of which Energy Vault's 10-K supplies for Cross Trails. What the filing does not disclose is the contracted price or the precise payment mechanics, which are typically held in the agreement itself rather than the narrative disclosure. The public record establishes that a 10-year commitment exists for a defined 57 MW / 2-hour system serving ERCOT; it does not, on its own, reveal the margin. That gap — between the disclosed structure and the undisclosed economics — is the normal boundary of what an offtake disclosure tells you, and recognizing it is the difference between reading the filing and reading the press release.

There is also a structural reason offtake agreements appear so prominently in storage disclosures rather than being left to the financial schedules: they bear directly on how revenue is recognized and on whether a project's assets sit on the developer's balance sheet or the customer's. When the developer retains ownership and contracts the output, as Energy Vault describes for parts of its portfolio, the offtake defines a multi-year service relationship the company accounts for over the contract life. When a project is sold outright, the offtake travels with the buyer. Either way, the existence, term, and counterparty of the offtake are facts a filer is expected to surface because they materially shape the revenue picture an investor is asked to evaluate — which is why the Cross Trails disclosure names the term, the capacity, the duration, and the market in the same passage that reports the start of construction.

The broader point is that "offtake agreement" is a precise, contract-defined concept, not a marketing label. It denotes a buyer's advance commitment to take a project's output for a stated term, and it is the mechanism by which an energy-storage project converts uncertain merchant revenue into the contracted cash flow that financing requires. When the term appears in an SEC filing alongside a named counterparty, a capacity figure, and a duration, it is describing the revenue spine of the project.