45Q Tax Credit: What Cement Plants Need to Know Before 2033

Cement kilns produce 10–15% CO₂ flue gas — one of the highest-concentration industrial streams available for capture. Under the OBBBA 2025, mineralization pathways now qualify for the full $85/ton 45Q credit, the same rate as geological storage. But the clock is ticking: construction must begin before January 1, 2033.

This analysis breaks down what cement operators need to know about 45Q eligibility, mineralization parity, the 2033 deadline, and the LCA requirement under IRS Notice 2024-60.

1. Why Cement Kilns Are Prime 45Q Candidates

A typical cement kiln emits 0.6–0.9 tons CO₂ per ton of clinker produced. With kiln flue gas at 10–15% CO₂ concentration, capture is more efficient per module than data center streams (3–5%). Higher CO₂ concentration means less energy per ton captured and higher throughputs.

At $85/ton for mineralized CO₂, a mid-sized cement facility capturing 100,000 tons annually generates $8.5M/year in 45Q credits — $102M over the 12-year credit window — before any CaCO₃ product revenue.

2. The Subpart RR Mineralization Exemption

Prior to the OBBBA 2025, mineralization qualified for only $50/ton — compared to $85/ton for geological storage. The parity provision established full rate equivalence, meaning cement operators choosing mineralization capture now generate the same federal credit as facilities injecting CO₂ underground.

Cement-specific advantage: cement kiln dust (CKD) contains ~40% CaO — the exact calcium feedstock needed for mineralization. Lafarge has confirmed CKD is available at no charge as a waste stream they want removed. This creates a zero-cost mineralization supply chain.

3. LCA Requirement Under IRS Notice 2024-60

For utilization 45Q claims, the IRS requires a third-party verified Life Cycle Assessment demonstrating net GHG reduction. For mineralization, this is straightforward: CO₂ is permanently locked into solid CaCO₃.

Cement facilities have an additional advantage — the CaCO₃ produced can feed back directly into concrete production as a high-performance filler, displacing virgin limestone mining and further reducing lifecycle emissions.

4. Meeting the 2033 Deadline

The 2033 deadline is not a compliance date — it's a hard cutoff for the enhanced $85/ton rate. Facilities that begin construction after January 1, 2033 receive only $50/ton, effectively halving the credit value.

Traditional CCS requires 18–36 months from FEED to commissioning. A cement facility that engages a vendor in 2030 has only 2.5 years for physical buildout — a window that's nearly impossible with conventional technology. Modular deployment in 5–12 months is the only pathway with sufficient timeline flexibility.