A credit for staying open, not for getting built
Section 45U is the zero-emission nuclear power production credit, created under the Inflation Reduction Act to support plants that were already running. There's no construction-start deadline because there's no construction requirement. To qualify, a facility must have been placed in service before August 16, 2022, and it can't have previously claimed a credit under Section 45J. In other words, this credit exists to keep the existing nuclear fleet economically viable, not to encourage new nuclear builds.
That fleet matters more than its share of headlines suggests. Nuclear power supplies close to a fifth of total US electricity and roughly half of all domestically produced zero-emission electricity. Before 45U, none of it was eligible for a federal production credit.
The mechanic nobody else uses: a gross receipts test
The base credit is 0.3 cents per kilowatt-hour, inflation-adjusted after 2024, and available on electricity produced and sold between the start of 2024 and the end of 2032. Where 45U diverges from every other PTC is how the credit amount is actually calculated. It isn't a flat rate. It phases down based on the plant's own gross receipts from electricity sales.
When a facility's gross receipts sit at or below 2.5 cents per kWh, it gets the full base credit. Above that threshold, the credit is reduced by 16% of the difference between actual gross receipts and the 2.5-cent floor. The credit phases out entirely once gross receipts hit roughly 4.375 cents per kWh. Meeting prevailing wage requirements multiplies the credit by up to five times, or up to 30%.
The practical effect is that 45U rewards plants that are economically marginal and penalizes plants that are already profitable on merchant power prices alone. A buyer diligencing a 45U credit isn't checking a construction timeline or a domestic content ratio — they're checking a plant's realized power price, its state and local subsidy stack, and how those inputs feed the gross receipts formula for the specific year the credits were generated. That's a financial underwriting exercise closer to project finance than to the compliance-driven diligence typical of a wind or solar transfer.
Where it stood through OBBBA and where the market sits now
Unlike several other credits that saw their timelines compressed, 45U came through the 2025 reconciliation act with its original 2032 phaseout intact — a reflection of the credit's bipartisan support in Congress. It remains eligible for both direct pay and transfer under Sections 6417 and 6418.
The market for these credits has been thin relative to their size. Roughly $200 million in 45U credits transacted in the spot market in 2025, even as estimates suggest as much as $1 billion in eligible credits sat on the sidelines, with operators still finalizing production calculations and buyers waiting for clarity on their own tax positions. When 45U credits do trade, they command some of the strongest pricing in the market, reflecting the low eligibility uncertainty that comes with an operating asset and a stable production profile, in contrast to construction-stage credits still carrying placed-in-service risk. That production stability is part of why capital chasing data center power demand keeps circling back to nuclear, a dynamic we covered in why data center demand is pulling new capital into the tax credit market.
OBBBA also broadened what counts as a "qualified nuclear facility," which is expected to widen the pool of eligible generation coming to market through 2026. For buyers who have mostly transacted in wind, solar, and storage, 45U is worth learning as its own credit rather than folding into a generic PTC framework — the underwriting questions, the pricing behavior, and the risk profile all run on a different track.