Recent IRS guidance has changed how commercial solar projects may establish eligibility for federal tax incentives. While these incentives remain available, certain early stage activities such as spending, procurement, permitting, or development work may no longer be sufficient on their own to demonstrate that a project has begun construction under current rules. In many cases, eligibility is now tied to evidence of physical construction activity within required timeframes.
For businesses considering solar in 2026, project timing has become a critical factor in securing valuable federal tax incentives. Delays in moving from development into construction may risk missing key eligibility requirements, making early planning and efficient execution more important than ever.
Understanding these requirements can help businesses move forward with confidence and avoid unnecessary scheduling challenges. With a local, in house team managing every stage of the process, Solar by Esmay helps reduce avoidable delays and keeps each stage aligned with current requirements.
Changes in eligibility rules
The updated IRS guidance affects how many commercial solar projects establish eligibility and how they maintain it during development and construction.
1. Eligibility can no longer be established through spending alone
The 5% Safe Harbor previously allowed certain developers to establish eligibility by incurring at least 5% of total project costs before key deadlines.
Under recent guidance, this approach is limited for certain technologies and project types, including larger scale solar and wind facilities. As a result, many projects are no longer able to rely solely on expenditures to establish eligibility under the safe harbor approach.
2. Physical construction is now the primary eligibility pathway
Current guidance places greater emphasis on demonstrating that physical work has begun on a project to establish eligibility.
Depending on project structure, qualifying activity may include:
- Installation of racking or mounting structures
- On site installation of major system components
- Off site manufacturing of project specific equipment under a binding contract
By contrast, activities such as equipment purchases, deposits, or general development spending may not, on their own, be sufficient to establish eligibility.
3. Continued construction activity is required to maintain eligibility
Previous guidance allowed a wider range of development activities to support ongoing eligibility once construction had begun, including permitting progress, engineering work, incremental expenditures, and contracting activity.
Under updated IRS rules, continued eligibility is now closely tied to ongoing physical construction.
Project timeline impact
The timing of when construction begins can affect both eligibility and the deadlines a project must meet to qualify for federal incentives. Projects that begin construction after July 4, 2026 are generally subject to a tighter completion window, which makes early planning especially important.
How Solar by Esmay supports commercial solar project planning
Federal tax incentives continue to support commercial solar investment, but recent IRS guidance has placed greater emphasis on the timing of physical construction as the primary factor in determining eligibility.
This shift increases the importance of early coordination across design, procurement, and installation, particularly where eligibility is tied to how and when physical construction begins. With more than 45 years serving businesses across Mohave County, Solar by Esmay's in house team manages each stage of the process to help reduce delays and keep projects aligned with current requirements.
For business owners exploring next steps, our commercial solar calculator provides a simple way to estimate system size and project potential.
