1. What “domestic content” means in solar

For solar projects, domestic content generally refers to where key equipment is manufactured, not where it’s installed.

The rules focus on two buckets:

Steel and Iron

100% must be U.S.-produced

Applies mainly to:

• • Racking

  • Mounting structures

  • Torque tubes
    
    

“Produced in the U.S.” means:

• • Melted, poured, rolled, and finished in the U.S.
    
    

Manufactured Products

Includes:

• • Solar modules

  • Cells

  • Inverters

  • Trackers (mechanical components)

  • Combiners, wiring harnesses, etc.
    
    

These do not need to be 100% U.S.-made.

Instead, they must meet a minimum U.S. cost percentage.

2. The domestic content percentage test

For manufactured products, you calculate:

(Cost of U.S.-manufactured components) ÷ (Total cost of all manufactured products)

Required percentages

• Projects that start construction before 2025: ≥ 40%

• Projects starting construction in 2025 or later: ≥ 55%
  
  

Residential projects currently have different treatment, but most utility-scale and C&I projects follow the thresholds above.

3. Why domestic content matters: the tax credit bonus

Meeting domestic content requirements can unlock a 10% bonus on top of base federal tax credits:

• Investment Tax Credit (ITC)

  • Base: 30%

  • With domestic content: 40%

• Production Tax Credit (PTC)

  • +10% increase in the per-kWh credit
    
    

This bonus stacks with other bonuses (e.g., energy communities, low-income adders).

4. How compliance is proven

Developers must:

• Obtain manufacturer certifications stating:

  • Country of manufacture

  • Cost breakdowns
    
    

• Maintain documentation for:

  • IRS audits

  • Tax equity diligence
    
    

• Perform a project-level cost calculation, not just component-level claims
  
  

There is no single government-issued “approved list”—compliance is based on documentation and calculations.

5. Common misconceptions

• ❌ “Using U.S.-assembled modules is enough”
  → Not necessarily; cells matter, and cost weighting matters.
  
  

• ❌ “Domestic content applies only to panels”
  → Racking, trackers, and inverters are often decisive.
  
  

• ❌ “It’s all-or-nothing”
  → Only steel/iron is 100%; manufactured products are percentage-based.
  
  

6. Practical strategy developers use

• Pair U.S.-made racking or trackers (heavy cost weight)

• Use U.S.-assembled modules where possible

• Mix U.S. and non-U.S. components to hit the percentage threshold

• Lock in supplier affidavits early (before tax equity)