A solar feasibility study is the first engineering step in any commercial or industrial (C&I) solar project. It determines whether a site is viable for solar — and if so, what the optimal system design looks like.
Think of it as the due diligence phase. Before anyone commits budget to plan sets, permitting, or procurement, the feasibility study answers: will this project actually work?
Why Feasibility Studies Matter
Skipping a feasibility study is one of the most expensive mistakes in C&I solar. Without one, teams discover deal-breaking issues during permitting or construction — when changes cost 10x more.
of C&I solar projects face significant redesigns during construction
Source: Solar Power World, 2025
A well-executed feasibility study catches these issues early:
- Structural limitations that reduce system size
- Electrical infrastructure that can't support the planned capacity
- Shading from adjacent buildings that kills production estimates
- Zoning or setback requirements that weren't accounted for
What Goes Into a Feasibility Study
Site Assessment
Review satellite imagery, building plans, and utility data. Identify roof age, condition, structural capacity, and available area.
Energy Modeling
Run production estimates using tools like PVsyst or Helioscope. Account for shading, orientation, tilt, and local weather data.
Electrical Review
Evaluate the existing electrical infrastructure — panel capacity, service size, and interconnection feasibility.
Financial Analysis
Model project economics including incentives (ITC, MACRS, SRECs), utility rate structures, and payback period.
Preliminary Design
Create an initial system layout with module placement, inverter sizing, and string configuration.
Feasibility Study vs. Full Design
| Feasibility Study | Full Design (Plan Set) | |
|---|---|---|
| Purpose | Determine viability | Construction-ready documents |
| Depth | Preliminary analysis | Detailed engineering |
| Deliverables | Report + layout | Stamped drawings + specs |
| Timeline | 3-5 days | 2-4 weeks |
| When to use | Before committing budget | After project approval |
Common Mistakes
Don't skip the structural assessment
Many teams assume a roof can handle solar without verifying. A structural assessment during feasibility can save tens of thousands in redesign costs later.
Other common pitfalls:
- Using Google Earth instead of actual site data — satellite imagery can be years old
- Ignoring utility rate changes — financial models based on current rates may not reflect future economics
- Overlooking AHJ requirements — local jurisdictions often have specific setback, fire code, or aesthetic requirements
- Not accounting for future BESS — if battery storage is on the roadmap, design for it now
Who Needs a Feasibility Study?
Every C&I solar project benefits from one, but they're especially critical for:
- Rooftop projects where structural capacity is unknown
- Sites with complex shading from adjacent structures
- Projects requiring utility interconnection upgrades
- Multi-building campuses with shared electrical infrastructure
Key Takeaways
- A feasibility study is the due diligence phase — it determines if a site is viable before committing budget
- It typically includes site assessment, energy modeling, electrical review, financial analysis, and preliminary design
- Skipping it leads to expensive redesigns during construction
- The best time for a feasibility study is before any commitments are made to plan sets or permitting
Frequently Asked Questions
How much does a solar feasibility study cost?
For C&I projects, feasibility studies typically range from $1,500 to $5,000 depending on site complexity, system size, and the level of financial analysis included.
How long does a feasibility study take?
Most feasibility studies are completed in 3-5 business days. Complex sites with multiple buildings or unusual structural requirements may take longer.
Can I skip the feasibility study and go straight to plan sets?
You can, but it's risky. Without feasibility, you may invest in full engineering only to discover the project isn't viable — wasting time and budget.