Unused renewable energy credits can still deliver value

Tax professionals are fielding questions about the residential clean energy credit now that 2026 new installations no longer qualify under current law. Many taxpayers assume that once a credit “expires,” any remaining benefit disappears with it. That’s not how this credit works.

Even though the ability to claim the residential clean energy credit has expired for expenditures made after Dec. 31, 2025, unused credits generated in prior years can still be carried forward. For practitioners, that distinction matters. Proper tracking and reporting can preserve thousands of dollars in future tax savings. Here’s what to keep in mind when working with carryforwards.

The expiration applies to new installations, not prior credits

The residential clean energy credit, formerly known as the residential energy efficient property credit, allowed taxpayers to claim a percentage of qualified costs for solar electric property, solar water heaters, geothermal heat pumps, small wind energy property, and fuel cells installed in a primary or secondary residence.

Under §25D, the credit is nonrefundable. That means it can reduce tax liability to zero, but it can’t generate a refund beyond taxes owed. When the credit exceeds a taxpayer’s tax liability in the installation completion year, the unused portion carries forward to the next tax year.

The key point: The carryforward provision remains in place for credits properly generated in earlier years. The expiration of the credit for expenditures made after Dec. 31, 2025, does not eliminate previously earned carryforwards. If a taxpayer installed qualifying solar panels in a prior year and could not use the full credit because of limited tax liability, that remaining amount continues to carry forward until fully used.

Nonrefundable credits require careful planning

Since the residential clean energy credit is nonrefundable, its value depends on future tax liability. Taxpayers with fluctuating income, large itemized deduction amounts or significant credits in later years may struggle to fully utilize the carryforward without proper planning.

Tax professionals should review projected income and credit interactions. Consider how the credit coordinates with other nonrefundable credits, such as the child tax credit or education credits. Ordering rules matter. Credits generally apply in a specific sequence, and once tax liability is reduced to zero, additional nonrefundable credits provide no immediate benefit.

Monitoring carryforward balances annually is essential. Many tax software programs track the remaining credit automatically, but practitioners should verify accuracy. Errors often arise when returns are amended, when taxpayers change preparers or when prior-year data is not fully imported.

Documentation remains critical

Carryforward claims require a clear audit trail. Practitioners should retain the following documents:

• A copy of the original Form 5695, Residential Energy Credits
• Invoices and proof of payment for the qualified expenditures
• Documentation showing when the original installation was completed
• Manufacturer certifications, when required
• Worksheets showing the computation and remaining carryforward

On subsequent returns, the carryforward is claimed using Form 5695. Even though the credit name and percentages have evolved over time, the underlying authority under §25D governs prior-year carryforwards.

If the IRS questions the credit years later, practitioners must demonstrate the credit was validly generated in the original year. The statute of limitations on the original return does not eliminate the need to substantiate the carryforward in a later year.

Common carryforward issues to watch 

Carryforwards can be lost unintentionally. Practitioners should be alert to several scenarios:

1. Filing status changes. Married taxpayers who previously filed jointly and later divorce may need to determine how the remaining credit is allocated. Generally, the credit follows the taxpayer who incurred the expenditure, but documentation is critical.
2. Property dispositions. If the residence is sold, the unused carryforward does not transfer to the buyer. The original taxpayer retains the remaining credit.
3. Insufficient tax liability year after year. In some cases, long-term low tax liability may prevent full utilization. Practitioners should consider legitimate planning strategies to increase taxable income in controlled ways if preserving the credit is a priority.

The practical takeaway

Credit expiration headlines can create confusion. The law distinguishes between generating a new credit and using an existing carryforward. For tax professionals, the message is clear: unused residential clean energy credits properly generated from qualifying expenditures completed before Jan. 1, 2026, remain available as carryforwards under current law.

Review prior-year returns carefully. Confirm carryforward balances. Coordinate credit usage with overall tax planning. Small oversights can result in permanently lost benefits.

When clients say, “I thought that credit ended,” the correct response is more nuanced. The opportunity to create a new credit may have closed, but the value already earned can still be used through carryforward rules. Proper documentation and reporting ensure it does not go to waste.