How a low-carbon cement producer financed kiln carbon capture with EACs

A US cement producer needed buyers to commit to the carbon reductions from its kiln capture project years before the first tonne of CO₂ would be stored. Sylvera's EAC assessment showed those buyers that the EACs could be issued, and that they would hold up to scrutiny once they were.

Industry: Industrial commodities / Carbon capture and storage

Region: United States

Use Case: EAC eligibility and integrity assessment to unlock offtake agreements ahead of first issuance

Results: Eligibility mapped, integrity risks documented, and offtake terms finalised — giving a first-of-kind kiln carbon capture project the contracted revenue certainty needed to move forward

Sylvera solutions used: EAC Assurance & Intelligence

‍The project

The producer runs a single-kiln cement plant in the US. Around 60% of the kiln's emissions are process emissions from turning limestone into clinker, and no change of fuel or power supply can remove them. That makes carbon capture and storage one of the few routes to a deep cut in carbon intensity.

The project fits an amine-based capture unit to the kiln's flue gas. A short pipeline carries the CO₂ to a Class VI well, where it is stored permanently in a deep saline formation. Together with renewable power purchase agreements, the project is expected to cut the plant's carbon intensity by more than two thirds.

The engineering is proven, but the economics are harder. For a first-of-a-kind kiln retrofit, the 45Q tax credit covers only part of the cost of capture, transport and storage. The producer needed a second source of contracted revenue before its board would commit to construction.

Why offtakes have to come before the plant

Projects like this are financed on contracted revenue. Lenders and boards want to know that the low-carbon output will be bought at a known price and for a known period before they approve the capital. As a result, offtakes are negotiated years before production starts.

The producer pursued two kinds of offtake:

• Physical offtake: selling low-carbon cement to customers with a higher willingness to pay, such as concrete producers supplying buildings with embodied-carbon limits and public projects with low-carbon procurement rules.
• EAC offtake: sold through a book and claim system, which separates the low-carbon attribute from the cement itself — opening up a much wider pool of buyers. Cement is heavy and costly to move, so most of it is sold within a few hundred miles of the kiln. The companies most motivated to cut cement-related emissions, such as hyperscalers building data centres, are often far outside that range.

What an EAC is, and what it is for

An EAC is a certificate representing the environmental attributes of one unit of product, in this case one tonne of cement shipped to a customer. It records the carbon intensity of that tonne, the baseline it is measured against and the reduction between the two. It is issued on a registry and retired by a buyer against a named claim.

The defining feature is that the attribute is separated from the physical product. The physical customer receives the cement with the baseline carbon intensity and accounts for it as conventional cement, while the EAC buyer retires the certificate and reports the reduction in its value chain emissions.

For corporate buyers, certificates offer a way to fund decarbonisation directly when their own supply chains are complex and slow to change. This is why the SBTi and the AIM Platform are making more room for certificates in corporate decarbonisation strategies.

How Sylvera was involved

Sylvera carried out an EAC assessment of the certificates the project expects to issue, before any offtake was signed. The assessment has two parts:

• The Eligibility Module tests whether the certificates can be issued under the framework the buyers have chosen.
• The Integrity Module looks at the quality behind each certificate.

Together they give buyers and the producer an independent view of what the EACs will deliver and what needs to change before first issuance.

The buyers' first question: can these EACs be issued?

Before quality came a more basic concern. No EAC had yet been issued for cement from a kiln with carbon capture, and buyers needed confidence that the certificates they were contracting for would exist, and conform to a recognised framework, when deliveries were due to start.

Standards for cement EACs are still emerging. The buyers chose the book and claim framework for cement and concrete published by the Center for Green Market Activation (GMA) and RMI. It sets requirements for:

• A carbon intensity threshold based on the Global Cement and Concrete Association's low-carbon rating
• Measurement through verified product-specific EPDs
• The treatment of carbon capture and storage
• Registries and physical customers

Because the framework is still being developed into a detailed rulebook, it gave the buyers a common reference point but left some requirements open to interpretation.

Sylvera's Eligibility Module tested each requirement against the facility's design, life cycle assessment and contracts. Each was rated as met, on track, action needed or not met, and the results were rolled into a single verdict.

This produced a short list of conditions the producer had to close before first issuance, such as adding a certificate of storage obligation to its storage agreement and making sure physical customers receive the baseline value rather than the post-capture carbon intensity. Because every condition was within the producer's control, the buyers could write them into the offtake agreements as conditions of delivery instead of carrying eligibility as an open risk.

Beyond eligibility: integrity, and the question of 45Q

Eligibility tells a buyer that an EAC can be issued, but not how much confidence to place in it. The Integrity Module scores each certificate across three pillars:

1. Carbon Accounting and CI Integrity
2. Additionality
3. Registry Integrity

ESG and co-benefits are assessed and reported alongside them.

Additionality and the 45Q question

Additionality matters because buyers use EACs to show that their spending changes how products are made. A certificate that pays for a reduction already required or fully funded by regulation does nothing for the atmosphere and sends no signal to the market. The SBTi makes a similar point about its draft rules for using EACs in value chain targets, saying that the criterion "is designed to drive transformation relevant to a company's value chain".

The buyers' main concern was regulatory additionality, and specifically the 45Q tax credit. If the federal government already pays for each tonne of CO₂ stored, a buyer paying for an EAC on top could be funding a reduction that would have happened anyway. The assessment addressed this directly:

• No federal, state or local rule requires the plant to capture CO₂, so the reduction is not mandated.
• 45Q is an incentive that carries no environmental claim, and at its current rate it covers only part of the cost of capture, transport and storage for a cement kiln.
• Sylvera rebuilt the producer's financial model and found that the project falls well short of its hurdle rate on 45Q alone, and that EAC revenue is what makes the investment viable.

Carbon intensity assumptions

The Integrity Module also raised issues the buyers had not asked about. The producer's declared carbon intensity relied on optimistic design assumptions, including capture efficiency, that the engineering evidence did not fully support. Sylvera ran a sensitivity analysis to show how far the carbon intensity — and so the reduction carried by each certificate — could shift if those assumptions are not met, giving buyers a clear view of the downside before they committed.

Can buyers stand behind the claim?

An EAC is only worth buying if the buyer can use it in its own reporting and defend that use to auditors, investors and the public. Much of the risk in the market sits here today. The SBTi, the GHG Protocol and the AIM Platform all give high-level guidance on how companies can claim certificates against their value chain emissions, but none yet sets detailed rules. That leaves the buyer's sustainability team to make judgement calls and carry the risk if those calls are later questioned.

For cement, a credible claim rests on a few points:

• No double counting: the reduction must be claimed only once, which means the physical customer reports the baseline value and no other registry or scheme issues against the same tonnes.
• Accounting alignment: the carbon accounting behind each certificate needs to line up with the way the buyer measures its own emissions, using comparable system boundaries and a conservative baseline, so a difference in method doesn't inflate the reduction the buyer reports.
• Value chain relevance: buyers need to show that the certificates relate to cement used in their value chain, such as in their own data centre construction.
• Supply chain clarity: buyers need to know whether the concrete producers and contractors between them and the plant can make a claim of their own.

Sylvera's assessment set out each of these points and the evidence buyers would need to support a claim under the frameworks they report against. Buyers' sustainability teams then had a documented basis for their claims and didn't have to interpret emerging guidance on their own.

What the assessment changed

With eligibility mapped and the main integrity risks set out, the negotiation moved from general uncertainty to a set of specific, documented points. The offtake terms:

• Made delivery conditional on eligibility at the time of issuance
• Priced the EACs on the reduction each one carries rather than per certificate
• Included provisions for any release of stored CO₂ and for re-testing additionality

The producer gained an independent account of its project that it could share with several buyers at once, along with a list of issues to fix while the design and contracts could still change. Contracted EAC revenue, alongside its physical offtakes, gives the project the revenue certainty it needs to move forward. Sylvera will refresh the assessment at first issuance, once operating data is available, and then for each vintage.

Setting a standard for quality

The market for EACs in industrial commodities is at an early stage, and buyers cannot yet rely on a standard alone to tell them which certificates are worth buying. In more established markets such as sustainable aviation fuel, certified volumes already vary widely in feedstock risk, data quality and the strength of chain of custody, and the same is likely to happen in cement, steel and chemicals as volumes grow.

Sylvera's EAC assessments are designed to make those differences visible, applying the same approach to integrity as Sylvera's carbon credit ratings so that buyers can direct their spending to the certificates that deliver the most. Pre-issuance assessments matter most, because they come at the point where buyer commitments decide whether a project gets built.