A stackable, performance-based framework for Environmental Attribute Certificates that grows the market while rewarding deep decarbonization.
Decarbonizing cement and concrete is a four-gigaton problem that will require every viable solution—from cheap SCMs to expensive CCS.
Excluding SCMs because they are 'already at price parity' misunderstands financing risk. Even 'cheap' solutions struggle to secure long-term offtake without contracted revenue.
Including everything without structure risks a race to the bottom, where buyers chase the cheapest certificates and underfund high-impact technologies.
We need a framework that includes all solutions but aligns usage with actual decarbonization potential—growing the market while preventing it from converging on the cheapest option.
Cement and concrete decarbonization is not one technology problem, it's a system problem:
We must both reduce emissions at the kiln (clinker substitution, process efficiency, fuel switching, CCS/CCU) AND use less clinker per cubic meter of concrete (SCMs, novel binders, admixtures, mix optimization).
To get anywhere near a 1.5C-aligned pathway, the sector must deploy all credible levers at speed.
Low-Cost, Mature
Fly ash, GGBFS, limestone
Mid-Cost, Moderate Risk
Emerging SCMs, novel cements
High-Cost, High-Impact
CCS, carbon mineralization
A functioning EAC market must recognize this portfolio reality instead of betting on one winner.
Many SCMs are already at or near price parity with OPC. If they don't require a 'green premium' to sell, they don't need EAC revenue. EACs should be reserved for 'hard' solutions like CCS.
The problem: This only holds in idealized markets with stable carbon prices and willing long-term buyers. In the U.S., even 'cheap' SCM projects struggle without contracted revenue.
We need all solutions, so all SCMs and decarbonization interventions should be eligible. Buyers can choose what to support, and the market will sort it out.
The problem: Without differentiation, buyers gravitate to cheapest certificates. High-impact pathways like CCS get chronically underfunded. Race to the bottom.
CTC believes the path forward is not either/or but both/and, with structure.
A durable EAC market for cement and concrete must:
Include the full range of solutions, from low-cost SCMs to CCS
Avoid crowding out high-impact options we need for full decarbonization
Provide bankable offtake signals so lenders can finance both 'cheap' and 'expensive' projects
Scale demand, not just price, so the market doesn't stall after early pilot deals
CTC believes the path forward is not either/or but both/and, with structure.
CTC's proposed approach starts from a simple idea: Let the market include all credible solutions, but align EAC usage with the actual physical decarbonization potential of each one.
All qualifying SCMs, new binders, process optimizations, CCUS projects, and other interventions can generate EACs.
Each solution is assigned a decarbonization factor (tCO2 avoided per tonne) AND a maximum substitution share—the fraction of a typical mix it can realistically replace.
Buyers can retire EACs from a given solution only up to that substitution share. To go beyond, they must stack EACs from additional, deeper-decarbonization technologies.
Take a simplified example:
SCM EACs (0-50%)
Buyers can retire SCM-linked EACs to cover up to 50% of embodied emissions. These will typically be lower priced because SCMs are more available.
Beyond 50%
To claim additional decarbonization, buyers must add CCS-linked or other high-abatement EACs. These are scarcer and more expensive, reflecting deeper impact.
The result: A base layer of abundant, lower-cost SCM decarbonization + a second layer of scarce, higher-cost CCS/novel binder decarbonization.
To achieve carbon neutrality, buyers must purchase EACs across the entire reduction spectrum. Toggle SCMs and drag demand to see market dynamics.
With SCMs
Full supply included
$67/tCOâ‚‚
55% buyers participate
Without SCMs
Supply constrained
$176/tCOâ‚‚
15% buyers participate
Key Insight
Including SCMs creates abundant supply for 0-50% reductions, keeping blended prices around $40-60/tCOâ‚‚. This enables broad buyer participation and a scalable market.
This structure naturally creates a market-driven price gradient. On the lower end of the abatement curve, there are many SCM projects—competition drives prices down. On the upper end, supply is limited; EAC prices are higher.
Buyers can't meet "100% decarbonized concrete" claims using only the cheapest certificates.
High-impact projects see higher EAC prices and more reliable offtake.
Blended portfolios (cheap + expensive EACs) can be structured to keep the effective green premium in a range that large, creditworthy buyers can stomach.
If the EAC market is designed so that only the most expensive technologies qualify, we risk very high green premiums, limited corporate participation, political pushback, and a small, slow, boutique market.
More buyers entering the market, because they can start with a blended, affordable decarbonization portfolio
More projects getting financed, because even "cheap" SCM projects now have contracted EAC revenue that de-risks financing, and advanced projects benefit from higher-priced EACs
A clearer pathway from "early adopters" to "mass market", as companies can gradually increase their share of high-impact EACs over time without facing a single, punishing price shock
In other words: we design the market to grow in the same direction we want the system to decarbonize—starting with lower-cost measures but always stacking toward deeper, system-wide solutions.
Today, there's a heated debate about what should and shouldn't be included in EAC systems. This debate exists because there are very few buyers for these environmental attributes right now. When the pie is small, everyone fights over who gets a slice.
But this framing misses the point. The goal of EAC design should not be exclusion—it should be growth. If we can't come together as an industry, we'll end up with a fractured book-and-claim system. Buyers won't follow any of them, and we fail to create the market we need.
The question is not whether SCMs should be in the EAC market or whether only CCS deserves support. The question is not how we divide up a few million tons of EAC purchases. The question is: how do we get to 100 million tons? How do we build a market at the scale of the problem?
If we can create a very large market, everyone wins—and we decarbonize the sector quickly.
CTC's answer is a stackable, performance-based EAC framework:
By aligning price, physical limits, and portfolio thinking, we can turn EACs from a niche instrument into a true market-making engine for low-carbon cement and concrete.
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