Solar ITC Compliance File: What EPCs Must Document

Before This Guide: Confirm the Deadline Question First

This piece assumes a project has already established, or is past the point of establishing, beginning of construction under Section 48E for the July 4, 2026 deadline. If that determination is still open, start with our EPC Action Guide covering the Physical Work Test, the 5% Cost Safe Harbor, and the ongoing litigation over IRS Notice 2025-42. What follows here is what happens after that question is settled: the paper trail the IRS actually expects, and the compliance obligations that don't end at commissioning.

Practical takeaway: A signed contract, a completed permit application, or finished engineering drawings prove intent. None of them prove beginning of construction on their own, and none of them satisfy MACR or FEOC documentation requirements either. The file has to be built separately, and it has to be built correctly the first time.

What Actually Satisfies the Physical Work Test

The IRS distinguishes between activity that establishes beginning of construction and activity that merely looks like progress. A signed procurement contract, completed engineering, or a permit application in progress does not, on its own, establish beginning of construction, and a compliance file that only documents those things will not hold up under review.

What the file needs:

• Dated, timestamped photographs of physical work: excavation, foundation pours, racking installation, conduit runs.
• Equipment mobilization logs showing crews and machinery on site before the relevant date.
• Contractor sign-in sheets or daily logs corroborating on-site activity.
• Manufacturing records for custom, project-specific components fabricated before the deadline, not generic inventory pulled from stock.
• A written narrative description of the physical work performed, prepared contemporaneously, not reconstructed months later for a filing deadline.

What the file should not rely on as standalone evidence: procurement contracts, permit submissions, engineering drawings, or environmental surveys. These support the broader narrative but do not independently establish beginning of construction. The IRS has specifically flagged scrutiny of what it calls artificial acceleration or manipulation of eligibility, meaning a token mobilization event staged for documentation purposes is a real audit risk, not a shortcut.

Where the EPC's job ends and tax counsel's begins: the project manager responsible for site activity is usually the best source for this evidence. But assembling raw, dated evidence is different from certifying that it's sufficient. Hand over the file; let tax counsel make the sufficiency call.

Documenting MACR Compliance: A Per-Facility, Ongoing Requirement

Material Assistance Cost Ratio compliance is not a one-time procurement check completed at panel order. It's calculated per qualified facility, which means a multi-block commercial project may need separate sourcing documentation for each inverter block, not one blended project-wide figure.

For projects beginning construction in 2026, the applicable threshold is 40% non-Prohibited-Foreign-Entity content for qualified facilities and 55% for energy storage technology, under IRS Notice 2026-15. This rises 5 percentage points annually toward a ceiling.

Notice 2026-15 provides three elective methods for establishing the MACR calculation: an Identification Safe Harbor, a Cost Percentage Safe Harbor, and a Certification Safe Harbor, each with a different documentation burden. Which one fits depends on how much visibility the EPC and its supplier actually have into the upstream supply chain. Get tax counsel input on which safe harbor to elect before assembling the file; switching methods after the fact is harder than choosing correctly the first time.

Minimum documentation for the file:

• Manufacturer-issued compliance certifications for each major component category, modules, inverters, racking, confirmed against the MACR threshold applicable to the year construction began.
• Country-of-origin documentation for cells and key upstream components, not just the final assembly location. US assembly does not cure Prohibited Foreign Entity-sourced cells.
• The underlying MACR calculation itself, retained and re-derivable on request, not just a pass or fail conclusion with no supporting math.

Recheck trigger: any mid-project supplier substitution requires a new MACR calculation for the affected components. Don't assume the original sourcing documentation still applies after a change order, even a minor one.

The Obligation That Outlives the Project Close-Out: 10-Year FEOC Recapture

This is the gap most EPC-facing content on the ITC deadline misses entirely. For Section 48E credits claimed in tax years beginning after July 4, 2027, a 10-year recapture rule applies: if a taxpayer makes a payment to a Specified Foreign Entity that grants that entity effective control at any point within 10 years of the project being placed in service, the full credit is recaptured. Not prorated. The entire amount, retroactively reduced to zero in the year the disqualifying payment occurs.

This is not a construction-phase risk. It's an operations-phase risk, and it attaches to contract types that EPCs routinely draft or recommend long after their own scope of work has ended:

• Warranty and replacement parts agreements with a foreign manufacturer.
• O&M contracts that hand ongoing system authority, monitoring, or control to a third party.
• Software licensing, including monitoring platforms, inverter firmware update agreements, or battery management system software, where the counterparty is a Specified Foreign Entity with authority over key aspects of system operation.

Exposure does not wait for a credit to actually be claimed, either. A developer who signs a warranty, software, or O&M agreement granting a Specified Foreign Entity effective control can create a disqualifying arrangement before construction even begins.

Why this matters for EPCs specifically, not just project owners: many EPCs either provide O&M themselves or recommend a provider and a standard service contract template at handover. A template drafted without FEOC awareness can create recapture exposure years after the EPC's own contractual liability period has closed, but the client will remember whose paperwork created the problem.

Practical step: review the standard O&M, warranty, and software licensing templates your firm hands clients at commissioning for effective-control language, not just the procurement contracts reviewed at construction start. This exposure runs for a full decade. Reviewing it once at close-out and never again is not sufficient.

What EPCs Should Hand to Tax Counsel, and What They Shouldn't Certify Themselves

A useful rule of thumb for dividing responsibility on a project's compliance file:

EPC responsibility: produce and preserve raw, dated, contemporaneous evidence. Photographs, logs, manufacturer certifications, sourcing documentation. Organize it. Timestamp it. Don't lose it.

Tax counsel or CPA responsibility: determine whether that evidence is sufficient to establish beginning of construction, whether the MACR calculation clears the applicable threshold, and whether a specific O&M or warranty arrangement creates effective-control exposure under the FEOC rules.

The failure mode to avoid is an EPC's project manager or senior staff signing off on sufficiency, "this satisfies the Physical Work Test," "this vendor is FEOC-compliant", without that determination coming from someone qualified to make it. That exposes the EPC to liability for a legal conclusion it isn't positioned to make, and it doesn't actually protect the client if the determination turns out to be wrong.

Building the Compliance File: Action Checklist for EPCs

• Assign file ownership per project – one person responsible for assembling and maintaining the compliance file, not a folder everyone assumes someone else is updating.
• Capture Physical Work Test evidence in real time – dated photos and logs at the moment work happens, not reconstructed from memory during tax season.
• Confirm the MACR safe harbor election with tax counsel before assembling documentation – the three methods under Notice 2026-15 have different evidentiary requirements.
• Recalculate MACR after any supplier or component substitution – treat this as a standing trigger, not a one-time gate.
• Audit standard O&M and warranty templates for FEOC effective-control language – before handover, not after a client asks.
• Set a recurring compliance review, not a one-time close-out check – the FEOC recapture window runs 10 years past placement in service.
• Route sufficiency determinations to tax counsel – EPC staff assemble evidence; qualified professionals certify it.

Reslink's compliance-tracking tools can help EPCs organize and timestamp this documentation as projects move through construction, but the underlying legal determinations here should always go through a qualified tax advisor. This is genuinely high-stakes, fast-moving federal tax law, not a checklist item to automate past.

Frequently Asked Questions

Q1. What documentation does the IRS actually expect for a Physical Work Test claim?

Dated photographic evidence, mobilization and contractor logs, manufacturing records for custom components, and a contemporaneous written description of the work performed. Signed contracts, permits, and engineering drawings support the narrative but don't independently establish beginning of construction.

Q2. Does MACR compliance need to be re-verified after a project is built?

Yes, for any change in sourcing. The calculation is per facility, and a supplier substitution or change order affecting sourced components requires a new calculation for the affected scope, not reliance on the original documentation.

Q3. What is the 10-year FEOC recapture rule, and who does it actually affect?

For Section 48E credits claimed in tax years beginning after July 4, 2027, a payment to a Specified Foreign Entity that grants effective control at any point within 10 years of placement in service triggers 100% recapture of the credit. It affects project owners directly, but the contracts that create this exposure, warranty, O&M, software licensing, are often drafted or recommended by the EPC at handover.

Q4. Should the EPC certify beginning-of-construction or MACR sufficiency itself?

No. The EPC's role is to produce and preserve raw, contemporaneous, dated evidence. The determination of whether that evidence is sufficient belongs to the project's tax counsel or CPA. This distinction matters if the determination is ever challenged.

Q5. How is this different from the July 4, 2026 deadline guidance?

That's a separate question, covered in our EPC Action Guide, about whether and how a project establishes beginning of construction before the deadline. This guide assumes that question is settled and covers what documentation and ongoing obligations follow from it.

Q6. Can a client's O&M provider trigger FEOC recapture without the EPC's involvement?

Yes, if the EPC recommended the provider or the contract template and that agreement later grants a Specified Foreign Entity effective control, exposure exists regardless of who signs the final contract. This is why reviewing standard templates for effective-control language before handover matters, not just at the point of an actual dispute.

Q7. Is this documentation requirement different for battery storage components?

Battery storage retains ITC eligibility through 2033 and is not subject to the July 4, 2026 construction deadline, but it is subject to its own MACR threshold, starting at 55% for 2026, higher than the 40% threshold for solar generation facilities, and to the same 10-year FEOC recapture exposure through warranty, O&M, and battery management software agreements.

Sources

• Winston & Strawn, "One Big Beautiful Bill – Solar and Wind PTCs and ITCs" – confirms the 10-year recapture period begins on the placed-in-service date, applies to ITCs claimed for tax years beginning after July 4, 2027, and results in 100% recapture on a qualifying payment.
• Energy-Storage.News, "FEOC compliance for BESS is a decade-long obligation" – supports the specific contract types (warranty, O&M, software licensing) that can trigger recapture, and confirms effective-control exposure can predate construction or claim.
• Novogradac, "Navigating the New Energy Landscape: FEOC and Beginning of Construction Rules for Section 48E, 45Y and 45X" – confirms recapture mechanics, including retroactive reduction to zero in the year the disqualifying payment occurs.
• Nixon Peabody LLP, "Foreign entities of concern, the material assistance rule, and IRS Notice 2026-15" – supports the three elective MACR safe harbor methods (Identification, Cost Percentage, Certification) and the 40%/55% starting thresholds for 2026.
• Morgan Lewis, "Meeting the MACR: IRS's Interim Guidance Addresses OBBBA's Material Assistance FEOC Limitation" – confirms Notice 2026-15 was issued February 12, 2026, and its scope.