Solar Subsidizer
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For US solar developers, EPCs and tax teams

Solar tax credits and tariffs, answered with the source behind every figure.

Find out whether a project clears the prohibited-foreign-entity rules, whether it earns the domestic content bonus, and what its imports will cost once every duty is applied. Each figure is traced to the statute, notice or proclamation it came from.

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Rules are transcribed from primary sources. Where the platform has no source for a figure, the answer comes back indeterminate instead of guessed.

The three tests

Three questions every US solar project now has to answer

Each one depends on different facts and different dates. Getting one wrong can cost a project its credit or blow its import budget.

45Y · 48E

Prohibited foreign entities

Did too much of the project come from a prohibited foreign entity?

Since the 2025 amendments, a clean electricity project can lose its 45Y or 48E credit if it receives material assistance from a prohibited foreign entity. The test is a ratio of direct costs — or, under the IRS's interim Cost Percentage Safe Harbor, of the assigned percentages in its tables — and the threshold it has to clear rises with the year construction begins.

What it needs from you

  • A bill of materials with the direct cost of each item
  • Who made each item, screened against the lists
  • Supplier certifications where you rely on them
Bonus credit

Domestic content

Is enough of the project made in the United States to earn the bonus?

The domestic content bonus adds to the credit when enough of the manufactured products' cost is US-made. The IRS elective safe harbor assigns every component a share of cost — cells, glass, frames, inverters, tracker parts — so you can compute it without your suppliers' cost data.

What it needs from you

  • Which safe-harbor table fits the site
  • Which components were manufactured in the US
  • Attestations from the manufacturers
Customs

Tariffs and landed cost

What will these imports actually cost once every duty is applied?

Modules and cells can carry several duties at once: the general HTS rate, Section 301 on products of China, Section 232 on polysilicon and its derivatives, a minimum import price per watt, and safeguard duties. The order they stack in, and the caps some countries get, change the total.

What it needs from you

  • The HTS code and country of origin of each line
  • The entered value declared to customs
  • The customs entry date

How it works

From bill of materials to evidence pack

  1. Map the supply chain

    Add the manufacturers that built your equipment and the suppliers you bought it from.

  2. Screen every company

    Record which prohibited-entity lists you checked and what you found. The log is kept as evidence.

  3. Attach the proof

    Upload certifications and attestations, then say what each one proves and for how long.

  4. Run the determinations

    Get a result for each test, with the reason for every criterion and the rule it relied on.

  5. Hand over the evidence pack

    One ZIP a reviewer can open without the platform: the reasoning, the rules and the documents.

FEOC / material assistanceIndeterminate

Two criteria need evidence before this project can be settled.

  • Construction startContext
  • Threshold in forceContext
  • Direct cost on every lineMet
  • Prohibited-entity status of each lineNeeds evidence
  • Material assistance cost ratioContext
  • Ratio meets the thresholdNeeds evidence

What would settle it

A screening of the module manufacturer, or a supplier certification covering the modules.

Illustration. Real results also name the rule row and source behind each criterion.

Principles

An answer you can defend a year from now

Every number has a source

Thresholds, rates, floors and dates live in versioned rule tables, each transcribed from a primary source and linked to it. None are written into the code.

Three honest answers

Qualifies, does not qualify, or indeterminate. When the evidence isn't there, the result says so, along with exactly what would settle it.

Nothing is overwritten

A new run creates a new record linked to the one it replaces. What you relied on last year is still there, word for word.

Reproducible

Every determination carries a fingerprint of its inputs and rules. Run it again on the same facts and you get the same fingerprint.

The AI never writes a number

The assistant quotes the source documents. Any figure it drafts must appear in the quoted text or it is thrown away, and questions about a project go to the rules engine.

Changes find you

When a rule changes or a certification expires, every current result is recomputed and anything that moved is flagged for review.

Solar compliance glossary

The terms, in plain language

Beginning of construction
When work on a project is treated as having started. It fixes which year's thresholds apply.
Placed in service
When the facility is ready and available to do its job, such as generating electricity.
Prohibited foreign entity
A specified foreign entity or foreign-influenced entity, as defined in 26 U.S.C. § 7701(a)(51).
Material assistance cost ratio
The share of a project's direct costs for manufactured products that does not come from prohibited foreign entities.
Domestic content bonus
An increase in the credit for projects whose steel, iron and manufactured products meet the US-content requirements.
Elective safe harbor tables
IRS tables that give each solar component a fixed share of cost, used to calculate the domestic content percentage.
HTS code
The Harmonized Tariff Schedule classification of an imported product. It decides which duties apply.
Entered value
The value declared to US Customs when goods enter the country. Percentage duties are calculated on it.
Minimum import price
A floor price per unit. Goods entered below it owe an additional duty on the difference.
Section 232
Duties imposed on national-security grounds. A 2026 proclamation applies them to polysilicon and its derivatives, including cells and modules.
Section 301
Additional duties on products of China, imposed after an unfair-trade-practices investigation.
AD/CVD
Antidumping and countervailing duties, set by Commerce Department orders against specific countries and producers.

The thresholds, rates and dates these terms refer to are published in full — each with the window it applies in and a link to the statute, notice or proclamation it came from.

Rates & thresholdsImport duty calculatorSolar components

What it doesn’t do yet

Known gaps, stated up front

Where the platform has no primary source for a rule, it reports the gap rather than filling it with a likely-looking number.

  • Antidumping and countervailing duty orders are not loaded, so that layer is shown as not evaluated rather than as zero.
  • 45X manufacturing credits for components are not evaluated yet.
  • Domestic content tables exist only for solar PV. Storage projects get an indeterminate result that names the missing table.
  • The Section 232 exemption for trade-agreement partners is recorded but not applied automatically.

See it on a real bill of materials

Create an organization, add a project, and run all three tests.

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