Understanding the 2025 Federal Tax Law: Strategic Implications for Energy Engineers and Clean Energy Projects

The passage of the 2025 tax law, widely referred to as the “One Big Beautiful Bill,” marks a turning point for how energy efficiency and clean energy projects will be planned, financed, and delivered in the United States. While the legislation preserves key incentives, it also accelerates several phase-outs, introduces tighter compliance requirements, and reshapes the Opportunity Zone (OZ) program.

For energy professionals, particularly those involved in high-performance building design, energy audits, renewable integration, and energy modeling, understanding these changes is critical. Engineers and consultants must now not only design for performance, but also for eligibility and documentation across evolving federal tax programs.

Energy Tax Incentives: What Remains and What Requires Urgency

Section 179D: Energy Efficient Commercial Building Deduction

Section 179D remains a foundational incentive for design professionals working on tax-exempt buildings. For projects that begin construction by June 30, 2026, energy service companies (ESCOs), engineers, and architects can continue to receive allocations of the deduction from tax-exempt building owners such as municipalities, universities, and nonprofits.

While not all firms may need the deduction immediately, it is advisable to bank these deductions through carryforward. This approach provides flexibility to apply the benefit against future income when the firm’s tax position changes.

Section 48 and 48E: Investment Tax Credit

The Investment Tax Credit (ITC) continues to apply to solar and wind energy systems. Projects that begin construction before July 4, 2026, are exempt from phaseout schedules introduced in the 2025 tax law. After this date, solar and wind projects must be placed into service by December 31, 2027, in order to be eligible to claim the Section 48E ITC.

Critically, compliance with Domestic Content requirements becomes mandatory for public and not-for-profit owned projects over 1MW beginning construction in 2026 using the Direct (Elective) Pay method for Section 48E. Some of the new Foreign Entities Of Concern (FEOC) requirements are now in place for Section 48E as well. FEOC materials assistance checks begin with projects starting in 2026. Documentation must clearly establish that project components and financing structures meet these new eligibility rules.

Section 48 avoided FEOC requirements altogether and remains in place through 2034 before phasing out. This covers projects that began construction prior to 2025 and any projects that contain geothermal technology for both heating and cooling and power generation applications.

Section 30C: EV Charging Infrastructure

The credit for electric vehicle (EV) charging stations and alternative refueling infrastructure will now sunset for all projects not placed in service by June 30, 2026. Energy professionals designing mixed-use, multifamily, or commercial facilities should consider accelerating installation timelines to ensure eligibility.

Direct Pay and Credit Transferability

Both mechanisms remain powerful tools in monetizing energy tax credits. Direct pay enables tax-exempt entities to receive reimbursement from the IRS for eligible clean energy investments. Transferability allows companies with insufficient tax liability to sell credits to third-party buyers.

However, these tools are now tied to enhanced compliance expectations particularly with projects over the 1MW threshold. Successful use requires well-documented project structures, adherence to prevailing wage standards, and confirmation of ownership and sourcing that avoids disqualifying entities.

Prevailing Wage and Apprenticeship (PWA) Requirements

One of the most important elements retained from the Inflation Reduction Act is the PWA framework. For projects exceeding 1 megawatt in capacity, full credit value is contingent on meeting prevailing wage and apprenticeship thresholds. This includes maintaining accurate records of wage rates, verifying contractor and subcontractor compliance, and ensuring participation of registered apprentices.

PWA compliance is not a one-time obligation. Projects must continue to track and document compliance for five to ten years, depending on the specific credit. Firms must begin real-time tracking from day one. Incomplete documentation or post-installation gaps can lead to partial or total forfeiture of credits.

Walker Blue strongly advises project teams to treat PWA with the same rigor as energy performance specifications. This includes building compliance tracking into standard project workflows and delegating responsibility to a qualified partner to avoid costly oversights.

Section 45L: New Energy Efficient Home Credit

Section 45L offers up to $5,000 per unit for residential and multifamily housing that meets ENERGY STAR or Zero Energy Ready Home standards. This credit is scheduled to expire for units acquired or leased after June 30, 2026. Design professionals involved in green housing developments should coordinate closely with certification teams to ensure that qualified homes are delivered and occupied in time.

MACRS Depreciation for Energy Property

The five-year accelerated depreciation option under the Modified Accelerated Cost Recovery System (MACRS) has been repealed for energy projects that begin construction after December 31, 2024. This change will impact solar, combined heat and power (CHP), and geothermal projects where early cost recovery was a critical part of the return model.

Section 45X: Advanced Manufacturing Credit

This credit remains in place for manufacturers producing qualifying clean energy components in the U.S. However, eligibility has narrowed. Projects involving foreign ownership or disqualified sourcing will no longer qualify. Wind-related components begin to phase out after 2027. This adds urgency to domestic manufacturing and supply chain partnerships.

Additional Tax Updates for Engineering Firms

• Bonus Depreciation is reinstated at 100 percent for qualifying property acquired after January 19, 2025.
• Section 179 Expensing has increased to a 2.5 million dollar cap with a 4 million phaseout threshold, providing flexibility for mid-sized firms.
• Section 174 R&D Expensing is restored. All companies can pull forward amortized R&D costs into 2025, while smaller taxpayers can choose to amend past filings. Engineering and energy modeling firms should reevaluate prior strategies under this rule change.

Opportunity Zones: Key Changes and Long-Term Strategy

Opportunity Zones (OZs) are now embedded within a permanent federal framework, with tract redesignation occurring every ten years. The next designation cycle opens on July 1, 2026, and allows states to select only 25 percent of eligible census tracts. Community and development stakeholders should begin advocacy efforts now.

Investments made after 2026 benefit from a new five-year deferral and an automatic 10 percent basis step-up, replacing the more complex seven- and ten-year tiers from the original program. For rural tracts, a 30 percent basis step-up and a reduced substantial improvement threshold now apply.

Expanded reporting obligations for OZ funds and investors will begin in 2027. Energy professionals advising on OZ-aligned projects should prepare to support data collection for revised IRS forms, likely to include detailed performance, community impact, and capital tracking.

Recommended Actions for Energy Engineers and Project Teams

1. Secure 179D Allocations Early
   Prioritize projects that begin construction before June 30, 2026. Even if the deduction is not currently needed, capturing and carrying it forward can preserve future tax value.
2. Align Solar and Storage Timelines with ITC Phaseout
   Target construction starts before July 4, 2026. Ensure all procurement and ownership records are in place to satisfy domestic content requirements.
3. Initiate PWA Compliance at Project Launch
   Track labor, wage rates, apprenticeship participation, and documentation beginning at contract execution. Continue tracking throughout the required post-service period.
4. Support OZ Planning for 2027 Designation Cycle
   Begin early engagement with local and state leaders. Prepare capital planning models to incorporate the new deferral schedule and rural incentives.
5. Reevaluate R&D Strategy and Bonus Depreciation Planning
   Use the restored flexibility in Section 174 to restructure past deductions and time future claims for maximum benefit.

Conclusion

The 2025 tax law presents both challenges and opportunities for energy professionals. Those who act early, track carefully, and collaborate across disciplines will continue to unlock substantial value for clients and stakeholders. Design professionals, ESCOs, and energy engineers are not just implementers of sustainable infrastructure, they are now stewards of compliance, tax strategy, and long-term project viability.

This article was written by Walker Blue, LLC. Josh Howes, CEO and David Diaz, CSO.

Walker Blue is a national leader in energy tax incentives and energy engineering, specializing in 179D and 45L tax certifications, ITC, domestic content, and prevailing wage compliance.