Is Solar Still 5-Year Property? What Changed for Projects That Started After 2024

TL;DR: Congress removed solar and wind from the five-year property list for anything that began construction after December 31, 2024. A separate five-year route is still open, but it runs on a different clock and a different set of definitions. Clearing it can mean a full first-year deduction. Missing it means the deduction arrives over decades instead, and the IRS has not published what recovery period a stranded project lands on.

What Section 70509 Actually Did

Congress did not write a new rule about solar. It deleted a line.

Section 70509 of P.L. 119-21, titled "Termination of Cost Recovery for Energy Property," amends section 168(e)(3)(B)(vi) of the Internal Revenue Code by striking subclause (I) and renumbering the two subclauses that were left. That is the entire operative text. The statute never says the words "solar" or "wind," because it removes a subclause by its number rather than by quoting what it said.

The IRS said out loud what came out. From the What's New section of the 2025 Instructions for Form 4562: "Section 70509 of P.L. 119-21 removed solar or wind energy property from the definition of 5-year property under section 168(e)(3)(B)(vi). This applies to solar or wind energy property beginning construction after December 31, 2024."

Two details carry the weight here. The trigger is beginning of construction, not placed in service. And there is no transition rule, no grandfather clause, and no binding contract exception. The effective date provision in section 70509(b) is one sentence long and gives exactly one test.

Key Point: If construction began on or before December 31, 2024, none of this touches you. If it began after, the old five-year classification is gone.

Why the Door That Is Still Open Runs on a Different Clock

Striking subclause (I) did not empty the energy category out of the five-year list. Clause (viii) of the same subsection is still on the books, and it reaches three things: a qualified facility as defined in section 45Y(b)(1)(A), qualified property under section 48E(b)(2) that is a qualified investment under section 48E(b)(1), and energy storage technology under section 48E(c)(2).

It is worth being precise about where that clause came from, because it would be easy to read the 2025 law as closing one door and opening another. It did not. Clause (viii) traces to the Inflation Reduction Act, section 13703 of P.L. 117-169. Section 70509 only did the striking.

The definitions matter more than the label does. A section 45Y qualified facility is a facility owned by the taxpayer, used for the generation of electricity, placed in service after December 31, 2024, with a greenhouse gas emissions rate not greater than zero. Solar and wind clear that emissions test comfortably.

The dates are where it gets uncomfortable. Section 70509 runs on when construction began. Clause (viii) runs on when the property was placed in service. In the Form 4562 instructions, the IRS describes clause (viii) as applying to property placed in service after 2025. So a project that broke ground in early 2025 and was energized later that same year is standing in a gap: too late for the old rule, and by the IRS's own description, too early for the new one. I could not find the statutory source for that "after 2025" qualifier, and section 45Y(b)(1)(A) itself says "placed in service after December 31, 2024." That discrepancy is real, and it needs resolving with your preparer before you file rather than after.

Key Point: Two provisions, two different dates, two different events. Your construction start date decides whether you lost the old rule. Your placed-in-service date decides whether you reach the new one.

What This Costs You If You Get It Wrong

The recovery period is not an accounting detail. It decides whether the deduction shows up this year or across the next several decades.

P.L. 119-21 reinstated the 100% special depreciation allowance for qualified property acquired and placed in service after January 19, 2025. The Form 4562 instructions define qualified property for that allowance as tangible property depreciated under MACRS "with a recovery period of 20 years or less."

Five-year property clears that test with room to spare. So an array classified as five-year property, placed in service in 2026, can be a full first-year deduction against your income. Take the same array at the same cost, put it outside the five-year list, and everything depends on what recovery period it lands on instead. If that period runs longer than 20 years, the special allowance is zero and you are recovering the cost on an ordinary schedule.

Put a number on it. On $1.2 million of solar treated as five-year property with the 100% allowance, the entire $1.2 million is deductible in year one. On a long schedule, year one is a small fraction of that and the rest arrives in slices for as long as you own it. The money is not lost. It is just deferred far enough out that most investors would not plan around it.

Key Point: The gap between these two outcomes on a single project is usually larger than the cost of finding out which one applies to you.

Why This Is Now a Documentation Question

Look at what section 48E(b)(2) actually reaches. Qualified property is tangible personal property, or other tangible property that is not a building or its structural components, used as an integral part of the qualified facility, on which depreciation is allowable, and either constructed by the taxpayer or newly used by the taxpayer.

Read that with a rooftop array in mind. The panels are tangible personal property and nobody argues about them. Racking bolted through a roof membrane, conduit run inside a wall chase, an inverter mounted to a structural column, and the service upgrade in the electrical room are a different conversation. Some of that is equipment. Some of it becomes part of the building. The statute draws the line and does not tell you where it falls on your particular roof.

That is not a question anyone answers from an invoice total. It gets answered component by component, with the engineering written down, which is exactly what an engineering-based cost segregation study produces. Desktop estimates and rule-of-thumb allocations were always the weaker option. On a provision that turns on whether a specific component is a structural component of the building, they are not usable at all.

Key Point: The classification question and the cost segregation question have become the same question.

The Part Nobody Has Answered Yet

Two things are genuinely open, and both matter before you build a projection on any of this.

The first is the 2027 sunset. Section 45Y(d)(4)(A) says that section does not apply to an applicable facility placed in service after December 31, 2027, and section 48E(e)(4) says the same for qualified property that is part of an applicable facility. An applicable facility is one that uses wind or solar to produce electricity. The open question is whether those terminations reach through into the depreciation classification. Clause (viii) cross-references only the definitional subsections, and the termination provisions sit outside every one of them, which argues the five-year treatment survives the credit sunset. Cutting the other way, both terminations are written broadly, as "this section shall not apply." The IRS has published nothing either way. This one is contested, and anybody telling you it is settled is guessing.

One wrinkle inside that: section 48E(e)(4)(C) carves energy storage technology out of the termination. The battery may not sit in the same position as the panels.

The second open item is what happens to a project that clears neither door. Construction began after December 31, 2024, so the old subclause is gone. The project was placed in service before the window the IRS describes for clause (viii), or the facility does not meet the section 45Y definition. There is no published answer on what recovery period applies in that case. I am not going to fill that hole with a guess. It is a live question, and it is the one to bring to your preparer with your actual dates in hand.

Key Point: Get your beginning-of-construction date and your placed-in-service date documented now, while the records are fresh. Every question in this article turns on those two dates.

Frequently Asked Questions

Did section 70509 change anything for solar projects already in service?

Not if construction began on or before December 31, 2024. The effective date in section 70509(b) turns on when construction began, not on when the property was placed in service, and there is no separate rule for property already in service.

Does this affect the solar tax credit?

No. Section 70509 amends section 168, which governs depreciation. The credits under sections 45Y and 48E are separate provisions with their own rules and their own termination dates.

What does beginning of construction mean here?

Section 70509 does not define it. The IRS has used physical work tests and cost safe harbors for beginning of construction under other energy provisions, and which standard applies here is a question for your tax professional. Whatever the answer, it should be documented at the time rather than reconstructed later.

If my project qualifies under clause (viii), do I still get 100% bonus depreciation?

Five-year MACRS property acquired and placed in service after January 19, 2025 meets the recovery period test for the reinstated 100% allowance, which the Form 4562 instructions define as MACRS property with a recovery period of 20 years or less. The other requirements for the allowance still have to be met on their own terms.

Does this apply to a rooftop array on a building I already own?

The construction start date for the array controls, not when you bought the building. The split between equipment and structural components matters here too, because section 48E(b)(2) excludes a building and its structural components from qualified property.

What about the battery?

Energy storage technology under section 48E(c)(2) is listed in clause (viii) alongside the facility and the qualified property. Section 48E(e)(4)(C) also carves energy storage out of the 2027 termination for wind and solar facilities. Storage may sit in a different position than the panels do.

Is a virtual walkthrough enough to document the component split?

No. An engineering-based study includes an in-person site visit by a trained professional. When the question is whether a specific piece of equipment is a structural component of the building, that determination gets made on site.

What recovery period applies if the project qualifies under neither rule?

There is no published answer. The IRS has not issued guidance addressing that case, and I am not going to guess at it in writing. Bring your construction start date and your placed-in-service date to your preparer.

Key Takeaways

• Section 70509 of P.L. 119-21 removed solar and wind from the five-year property list for property the construction of which begins after December 31, 2024. There is no transition rule and no grandfather clause.

• A separate five-year route survives at section 168(e)(3)(B)(viii), covering a section 45Y qualified facility, section 48E qualified property, and energy storage technology. It came from the Inflation Reduction Act, not from the 2025 law.

• The two provisions run on different events. One turns on when construction began, the other on when the property was placed in service.

• The stake is the 100% special depreciation allowance, which reaches only MACRS property with a recovery period of 20 years or less.

• Section 48E(b)(2) excludes a building and its structural components, which makes the component-by-component split an engineering question rather than an invoice question.

• Whether the 2027 terminations in sections 45Y(d)(4) and 48E(e)(4) reach the depreciation classification is unresolved. So is the recovery period for a project that clears neither door.

Where to Start

If you have a solar or wind project that broke ground after 2024, the first move is not a tax opinion. It is getting the dates and the components documented while the construction records are still easy to pull.

I offer a no-cost analysis through my relationship with CSSI. No obligation and no pitch, and if a study will not pay for itself on your property, I will tell you that plainly. You do not need to gather documents before we talk. Bring what you know and we will work out the rest.

Book a time at calendly.com/david-wiener/cs, or call 770-224-8504 and choose option two.

For the broader picture on how the 2025 law reshaped first-year deductions, see Bonus Depreciation in 2026. Primary sources for this article: the 2025 Instructions for Form 4562 and the current text of 26 U.S.C. § 168.

This article is educational and is not tax advice. Your situation depends on facts this article cannot see. Talk to your own tax professional before acting.