Two cell manufacturing routes in the United States and the 45X credit

An opinion piece by Sekhar Tatineni, technology VP at ES Foundry, published by pv magazine on 23 September 2026, separates two routes for solar cell manufacturing in the US. In the first, the plant starts from the unprocessed "gray" wafer and runs P/N junction formation, passivation and metallization. In the second, it receives the "blue" wafer, junction already formed, and only finishes it.

The distinction carries a tax consequence. The final regulations for the Section 45X credit, T.D. 10010, published in the Federal Register on 28 October 2024, condition the benefit on substantial transformation of the input into an eligible component and exclude minor assembly. The text does not settle the blue wafer case by name, but it sets the test that resolves the argument.

For whoever finances a plant, the difference changes the size of the investment. A gray-wafer line needs the diffusion and deposition blocks, with more capital tied up and longer commissioning than a finishing line. The return on that capital depends on the domestic step being recognised by the credit and by origin rules.

Until the qualifying step is described in process terms, investors price regulatory risk on the most expensive part of the plant. A definition written around process, rather than location, is what makes that capital financeable.