MACRS Depreciation + Section 48E: How Businesses Save on Commercial Solar in 2026

The Section 48E investment credit and depreciation affect a solar project's economics in different ways. A credit reduces eligible tax liability; depreciation is a deduction whose value depends on the taxpayer's circumstances. Neither should be presented as an automatic discount on an installation invoice.

This guide explains the distinction, the relationship between credit and depreciable basis, and the records to discuss with a tax adviser. Sundra's role is commercial solar planning and installation; your qualified tax adviser determines the treatment that applies to your entity and project. This is general information, not tax advice or a determination that a particular project qualifies.

How does the Section 48E credit work?

Section 48E has a base rate of 6% and an alternative 30% rate when the applicable conditions are met.

Qualifying facilities with maximum net output below 1 megawatt, measured in alternating current, have an exception to the prevailing-wage and apprenticeship requirements for that higher rate. Other qualifying projects can reach the higher rate through compliance with those requirements.

Do not infer eligibility from the rate alone. The facility, owner, construction history and other statutory conditions also matter. The IRS final regulations explain the capacity test, including treatment of integrated facilities.

Additional credits may depend on domestic content, location or a separate allocation process. They are not included in the example below. Ask the adviser to identify the supporting rule for each proposed addition.

How do depreciation and the credit interact?

The credit and depreciation use related but different calculations. The tax basis is generally reduced by half the energy credit when the applicable basis-adjustment rule applies. At a 30% credit rate, that leaves 85% of the otherwise eligible cost as the adjusted basis before any other adjustments.

Depreciation eligibility, recovery period and elections need separate review. IRS Publication 946 describes both new treatment for qualifying clean-electricity property and changes to older solar-property classifications. Calling every solar installation “five-year property” without checking its applicable category is insufficient.

The same publication describes a 100% special depreciation allowance for certain qualified property acquired and placed in service after January 19, 2025. That does not establish that every component, acquisition or taxpayer qualifies, or that the deduction produces an immediately usable cash benefit.

What does a worked tax example look like?

This hypothetical example isolates the mechanics. It assumes $200,000 of eligible cost, an available 30% credit, the half-credit basis adjustment, full eligibility for a first-year depreciation deduction and an illustrative 21% tax rate. It assumes the benefits can be used in that year. It excludes state taxes, financing, other basis adjustments and bonus credits.

The $170,000 deduction is not a $170,000 refund. Its assumed tax value here is $35,700. Changing the tax rate, deduction timing or ability to use the benefit changes the outcome.

The installer still charges the agreed project price. To compare tax effects with electricity value, maintenance and financing, use a separate solar return-on-investment calculation.

What eligibility dates and records need review?

Construction-start and placed-in-service dates can affect eligibility, but they are not interchangeable with signing an agreement or paying an invoice. Obtain project-specific advice on the evidence required for each.

IRS Notice 2025-42 describes the statutory termination of credits for applicable wind and solar facilities placed in service after December 31, 2027, with a construction-start exception. Have the adviser verify the currently applicable construction-start guidance and any subsequent legal developments before relying on that exception. This article does not determine safe-harbor eligibility.

The installation process guide separates engineering, permitting, construction and utility authorization. A tax eligibility date should not be turned into a contractor's completion promise.

How do sourcing restrictions differ from bonus credits?

Prohibited-foreign-entity material-assistance rules can affect eligibility for the underlying credit. They are not simply an optional domestic-content bonus requirement.

IRS Notice 2026-15 addresses facilities whose construction begins after December 31, 2025. Its material-assistance rules do not provide a general exemption merely because a solar facility is below the 1-megawatt threshold used for the wage-and-apprenticeship exception.

Keep the tests separate. Ask which sourcing documentation is needed, who supplies it and how equipment substitutions are reviewed. Avoid treating a country label or a manufacturer's marketing statement as a complete eligibility determination.

How do ownership and tax status change the analysis?

The party claiming a benefit must establish that it is entitled to it. A building owner buying electricity from a third-party-owned array should not assume it can also claim the system owner's tax benefits.

Eligible tax-exempt entities may instead use elective pay for qualifying credits. That is a separate mechanism, not a depreciation deduction against income tax the organization does not owe.

Homeowner incentives are also different. The IRS states that the residential Section 25D credit is unavailable for property placed in service after December 31, 2025. Do not apply commercial examples to a new residential installation.

What should be in the tax-review file?

Prepare an itemized project scope, ownership documents, acquisition and construction records, equipment information, placed-in-service support and any documentation relevant to higher credit rates or sourcing requirements. Have the adviser reconcile the proposed treatment with the taxpayer's ability to use the benefits.

Review commercial financing terms separately. A financing arrangement changes cash flow and may change ownership; it does not establish tax eligibility.

For a property in PA, NJ or DE, start the installation-scope conversation with Sundra before treating an illustrative tax benefit as your project budget. Provide the address, your electricity-use goals and known roof issues. Keep the proposed equipment, ownership arrangement and timing assumptions available for your adviser's review. An installation estimate and a tax determination answer different parts of the investment decision.

Sources

1. IRS final clean-electricity regulations, Bulletin 2025-12, Section 48E rates and the one-megawatt exception.
2. IRS Publication 946, property classification and special depreciation rules.
3. IRS Form 3468 instructions, investment-credit calculations and basis adjustments.
4. IRS Notice 2025-42, Bulletin 2025-36, statutory solar termination dates and construction-start guidance; confirm current application with a tax adviser.
5. IRS Notice 2026-15, material assistance from prohibited foreign entities.
6. IRS: Residential Clean Energy Credit, the separate residential credit's end date.