Federal Solar and Storage Tax Changes: Current Dates, Transition Rules, and Sources
Summary: Public Law 119-21, enacted July 4, 2025, ended the residential Section 25D clean-energy credit for expenditures after December 31, 2025 and added separate transition, leasing, and Prohibited Foreign Entity rules for business and manufacturing credits. It did not simply eliminate every commercial solar credit in 2027, make domestic content a universal eligibility mandate, or repeal transferability.
August 2026 update: Polysilicon import measures
On August 6, 2026, the White House issued a proclamation adjusting imports of polysilicon and its derivatives; the measure was published in the Federal Register on August 11, 2026 (document 2026-16400). The record identifies minimum import prices for specified polysilicon, ingot/wafer, cell, and module categories and a specified 15% ad valorem duty, with annexes, exceptions, and country-specific treatment that must be read together. The measures could affect supply-chain and purchasing assumptions, but they do not by themselves prove that every imported panel will immediately cost more: covered goods, exclusions, CBP implementation, and retail pass-through must be kept separate. Status: published and effective per its terms; implementation details remain with Commerce and CBP.
- White House proclamation, August 6, 2026
- Federal Register document 2026-16400, August 11, 2026
- Official Federal Register PDF (GovInfo)
What changed
Public Law 119-21, enacted July 4, 2025, ended eligibility for new residential Section 25D expenditures after December 31, 2025 and added separate transition, leasing, sourcing, and Prohibited Foreign Entity rules affecting business and manufacturing credits. It did not terminate every commercial solar or storage credit on one date.
Effective date
The law was enacted July 4, 2025, but its provisions use different effective dates, construction-start tests, placed-in-service deadlines, taxable-year rules, and guidance dates. The article identifies those separately; no single date substitutes for project-specific review.
Who is affected
Potentially homeowners, businesses, project owners, lessors, manufacturers, component suppliers, credit transferees, and tax advisers using Sections 25D, 45X, 45Y, 48E, or related elections. Ownership, completion date, construction start, placed-in-service date, technology, sourcing, labor, and taxpayer facts can change the result.
This is an educational federal-policy explainer, not tax or legal advice. Project ownership, construction start, placed-in-service date, credit section, sourcing, labor requirements, elections, and taxpayer facts can change the result.
At-a-glance status
| Topic | Position as of August 14, 2026 |
|---|---|
| Homeowner Section 25D | No new credit for expenditures after December 31, 2025. For an existing home installation, the expenditure is generally treated as made when the original installation is completed. |
| Business/utility solar under 45Y or 48E | The special solar/wind termination rule generally applies when construction begins after July 4, 2026 and the facility/property is placed in service after December 31, 2027. Earlier valid construction starts can receive different transition treatment. |
| Energy storage under 48E | Storage is excluded from the special solar/wind termination provision, but must satisfy its own eligibility, placed-in-service, labor, and PFE-related rules. |
| Domestic content | An optional bonus framework, not a blanket requirement that most components be U.S.-made. |
| Section 45X manufacturing | Still available for eligible U.S.-produced solar components; new PFE and integrated-component rules apply. |
| Transferability | Not repealed for 45X, 45Y, or 48E, but transfers to a specified foreign entity are restricted. |
Residential solar: the Section 25D cutoff
Section 70506 of Public Law 119-21 ends the Residential Clean Energy Credit for expenditures made after December 31, 2025. Under Section 25D(e)(8), an expenditure for an existing home is generally treated as made when the original installation is completed. For property connected with a newly constructed or reconstructed home, timing is tied to when the taxpayer’s original use begins.
A contract, deposit, or full payment in 2025 does not by itself preserve a new Section 25D credit when the original installation is completed in 2026. A taxpayer may have a different question about carrying forward an unused credit properly generated in an eligible year. The NerdVolt residential eligibility checker follows this completion-date treatment and returns zero for a new installation completed in 2026.
Commercial and utility solar: 45Y and 48E transition
The relevant investment-credit provision is Section 48E, not “48(e).” Sections 70512 and 70513 add a special termination rule for applicable wind and solar. For a covered solar facility whose construction begins after July 4, 2026, Sections 45Y and 48E are unavailable when the facility or property is placed in service after December 31, 2027. The special December 31, 2027 cutoff does not apply in the same way when construction validly began on or before July 4, 2026; all other qualification rules still matter.
IRS Notice 2025-42 supplies beginning-of-construction guidance. For covered facilities that had not begun construction before September 2, 2025, it generally makes the Physical Work Test the controlling method for this transition. Planning, financing, permitting, site clearing, and similar preliminary activity do not count. IRS Notice 2025-42 keeps a Five Percent Safe Harbor for a “low output solar facility” whose maximum net output is no greater than 1.5 MW AC. Continuity and placed-in-service rules must also be evaluated.
Energy storage is not subject to the solar/wind termination rule
Section 48E expressly excludes energy-storage technology from the special termination provision applied to wind and solar. That is not a blanket approval: storage must still be qualifying property and can be affected by basis, labor, tax, interconnection, ownership, and PFE restrictions. A solar-plus-storage project may need the components analyzed separately.
Third-party residential leasing limitation
Public Law 119-21 added a targeted Section 48E rule that can deny the credit for specified residential solar or wind property when the taxpayer rents or leases the property to a third party during the taxable year. This should not be paraphrased as a universal end to every solar lease or power-purchase agreement. Ownership structure, property type, credit section, placed-in-service date, and transition rules require project-specific review.
Domestic content: optional bonus, separate calculation
Domestic content is generally a bonus-credit path, not baseline eligibility. For a Section 48E project that otherwise qualifies for the full rate, satisfying the domestic-content rules can add 10 percentage points; otherwise the increase is generally 2 percentage points. The manufactured-product adjusted percentage is 50% for construction beginning during 2026 and 55% for construction beginning after December 31, 2026. Earlier transition percentages were 40% before June 16, 2025 and 45% from June 16 through December 31, 2025.
The rules treat structural iron and steel separately from manufactured products and use cost-based calculations. They are not a component-count test.
Prohibited Foreign Entity restrictions
The current statutory concept is a Prohibited Foreign Entity (PFE), not simply “equipment from certain countries.” The rules include specified foreign entities, foreign-controlled or foreign-influenced entities, ownership and effective-control tests, and material-assistance calculations. Contracts, licensing, operations, debt, officer appointment, and sourcing can matter.
Notice 2026-15 provides interim identification and calculation safe harbors. For projects beginning in 2026, the statute establishes different non-PFE material-assistance thresholds for different credits and technologies—for example, 40% for Section 45Y solar and 55% for Section 48E energy storage. These are non-PFE cost-ratio tests, not U.S. domestic-content percentages. Treasury and the IRS intend additional rules, and the statute calls for further guidance by December 31, 2026.
Section 45X manufacturing and transferability
Section 45X remains available for eligible solar components produced in the United States; the 2025 law did not impose a general 2027 termination on solar-component credits. The law added PFE restrictions and, for specified integrated components sold in taxable years beginning after December 31, 2026, a rule requiring at least 65% of total direct material costs of the secondary component to be attributable to qualifying U.S. primary components.
Transferability under Section 6418 was not repealed for 45X, 45Y, or 48E. Pre-filing registration and the other transfer rules still apply, and the law restricts transfers of listed credits to a specified foreign entity for taxable years beginning after July 4, 2025.
Reader checklist
- Homeowner: record the original-installation completion date, ownership, eligible costs, rebates, residence use, tax liability, and any prior-year carryforward.
- Project owner: identify the exact credit section, facility/property boundaries, construction-start evidence, continuity, placed-in-service date, ownership and leasing structure.
- Solar-plus-storage project: analyze solar and storage separately where the statute does.
- Bonus or sourcing claim: keep supplier certifications and the cost calculation for domestic content distinct from PFE material-assistance calculations.
- Credit transfer: complete registration and counterparty/PFE diligence before treating transfer proceeds as available.
Current uncertainty and review trigger
PFE implementation remains active. Notice 2026-15 is interim guidance, proposed regulations and replacement safe-harbor tables may alter compliance work, and further statutory guidance is due by December 31, 2026. This article should be reviewed when Treasury or the IRS publishes new PFE regulations or tables, and at least monthly through that date.
Official sources
- Public Law 119-21, especially sections 70506, 70512, 70513, and 70514.
- IRS FAQ FS-2025-05 and the Residential Clean Energy Credit page.
- IRS Notice 2025-42, beginning-of-construction requirements.
- IRS Domestic Content Bonus Credit hub.
- IRS Notice 2026-15 and the IRS PFE topic page.
- IRS Advanced Manufacturing Production Credit hub.
- Current Section 6418 text and the IRS transferability FAQ.
The IRS Residential Clean Energy Credit page correctly states that the credit is unavailable after December 31, 2025 but, as checked August 14, 2026, also retains older phaseout wording elsewhere on the page. This explainer uses the enacted statute and the August 2025 IRS modification FAQ for the cutoff.