Solar Tax Credit Analysis: How It Works, Who It Fits, and the Catch

How solar credits work after OBBBA

There are three ways a seller runs into solar credits.

• Home systems (Section 25D). The 30% residential clean energy credit does not apply to expenditures made after December 31, 2025 (IRC 25D(h), as amended by P.L. 119-21). It is no longer a 2026 planning tool.
• Owning a commercial project (Sections 48 and 48E). The clean electricity investment credit under Section 48E is a percentage of the project's cost. For wind and solar, OBBBA added a termination: no credit for property placed in service after December 31, 2027, unless construction began by July 4, 2026 (IRC 48E(e)(4) and its effective date). Notice 2025-42 tightened what counts as beginning construction. The older Section 48 credit applies only to projects that began construction before 2025.
• Buying credits (Section 6418). A project owner can sell its credit for cash to an unrelated buyer. The buyer pays less than face value, the payment is not deductible to the buyer and not income to the seller, and the credit can be transferred only once.

The two limits that bite in a sale year

Passive credit limits. Under Treas. Reg. 1.6418-2(f)(3)(ii), a purchased credit is treated as arising from a trade or business, and Section 469 applies. A buyer who does not participate in the project holds a passive credit, which can only offset tax attributable to passive income. Gain from selling a rental you held as a passive activity is generally passive income (Treas. Reg. 1.469-2T(c)(2)), so it can absorb purchased credits. Gain on a business you actively run, wages and portfolio gains cannot.

The general business credit limit. Section 38(c) caps business credits at your net income tax minus the greater of your tentative minimum tax or 25% of regular tax above $25,000. A large capital gain phases out the AMT exemption, and once tentative minimum tax exceeds regular tax, the cap drops to zero for credits that are not on the 38(c)(4) "specified credit" list. The Section 48 energy credit is on that list; Section 48E is not. Unused credits carry back one year and forward 20 (IRC 39).

Who it fits, and who it does not

• Fits: sellers of a passive rental whose sale year leaves regular tax comfortably above tentative minimum tax.
• Fits: owners who actually build or buy into a solar project and materially participate, with the project placed in service by the deadline.
• Fits: sellers who spread gain with an installment sale, so later years stay out of AMT and have room for credits.
• Does not fit: a business owner selling an active company, whose non-passive gain cannot absorb passive purchased credits.
• Does not fit: a one-year lump-sum sale that puts you in AMT; a 48E credit may sit unused until a later year.
• Does not fit: homeowners planning a 2026 residential system for the 25D credit, which has ended.

Worked example

Assumptions (engine, 2026 federal rules, married filing jointly, Texas): $150,000 of other income plus long-term capital gain from a sale, either all in 2026 or spread by an installment sale. The engine reports regular federal tax and any alternative minimum tax on top.

In the two larger years the couple owes AMT, which means tentative minimum tax is above regular tax and the Section 38(c) cap for a 48E credit is zero. A credit bought that year would carry forward instead of reducing the sale tax. In the smaller years there is room, subject to the 25% and passive limits. Numbers are illustrative engine output; the exact room depends on the full return.

IRS stance and audit risk

Transferability is statutory and the IRS runs a pre-filing registration system: each credit needs a registration number from the IRS before it can be sold, and both sides file Form 3800 elections. The risks are in diligence, not legality: a project that fails beginning-of-construction rules, prevailing wage and apprenticeship requirements, domestic content or prohibited foreign entity rules can lose some or all of the credit, and an excessive credit transfer triggers tax plus a 20% penalty on the buyer unless reasonable cause is shown (IRC 6418(g)(2)). Investment credits are also subject to recapture if the property is disposed of within five years (IRC 50), so purchase agreements allocate that risk and buyers often insure it.

Solar credits are not a listed transaction. Separately, the IRS has long challenged abusive solar promotions that sold credits on equipment that never existed or was never placed in service; a real, placed-in-service project with clean documentation is the line.

Costs and fees

• The purchase discount is the buyer's return; brokers and platforms take fees from one or both sides.
• Legal and tax diligence on the project, plus any recapture or credit insurance.
• Carryforward cost: a credit you cannot use this year loses value while it waits.
• For project owners: construction, interconnection, financing and operating risk, plus the new placed-in-service deadline.

How it compares with a Section 453 installment sale

An installment sale lowers the tax on a big gain by spreading it, often keeping each year out of AMT and in the 15% capital gain bracket longer. Credits work the other way: they need tax to offset and room under Section 38(c). That makes the two complementary. A lump-sum sale can leave purchased credits stranded; a spread sale can leave each year with regular tax above tentative minimum tax, where a credit is usable. For an active business seller, though, purchased passive credits rarely help with the sale gain at all.

See also oil and gas IDC for a deduction-based offset and year-end timing for splitting a closing across tax years.

How Hans helps

The $5,000 Big Sale Tax Analysis checks the passive, AMT and 38(c) limits in your actual sale year and in each year of an installment schedule, so you know whether a credit is usable before you buy one. It compares that against a cash sale, an installment sale, a 1031 and the other paths. Start with the one-year vs spread estimate.

Frequently asked questions