What a commercial solar feasibility study is
A commercial solar feasibility study is an early-stage, remote, evidence-based assessment of whether rooftop photovoltaic (PV) is worth pursuing on a specific UK commercial building. It answers four questions in writing: how much the roof could generate, what the financial return looks like over 25 years, whether obvious engineering or regulatory barriers exist, and whether the project is worth taking to the next stage — including whether a physical survey is worth commissioning.
It is not detailed design, structural certification, or an installer quote. It sits upstream of those steps — a pursue-or-park decision document that a board, landlord, or asset manager can read without specialist solar knowledge. Stage1Energy produces a 29-page feasibility dossier for £1,250 per site, delivered in five working days, with every material figure traced to its source.
If you are not ready to commission the full study, free screening on one building gives you a verdict, panel placement, and monthly generation profile within three working days — no card required.
Who orders a feasibility study
Commercial solar feasibility studies are commissioned by landlords screening a portfolio, estates teams evaluating a single asset, property developers testing a scheme before acquisition, and advisers who need an independent number their client can rely on.
- Commercial landlords — rank roofs across a portfolio before committing survey spend.
- Estates and facilities teams — build an internal business case for capex approval.
- Developers and investors — test whether solar improves IRR on a building before purchase.
- Consultants and advisers — obtain a sourced dossier to support client recommendations.
See building-type guides for warehouses, landlord portfolios, and commercial rooftops more broadly.
What is in the dossier
Every Stage1Energy feasibility dossier contains the same sections whether you book one roof or thirty:
- Written verdict — pursue or park, with system size, annual yield, and NPV stated plainly.
- 25-year financial case — capex build-up, payback, IRR, NPV, and hour-by-hour cashflow.
- Zone-by-zone roof layout — panel placement on satellite imagery with setbacks and exclusions.
- Four engineering screening flags — wind, structure, DNO (G98/G99), and planning permitted development.
- Sourced calculation workings — formula, result, and reference for every material figure.
Read the full structure in the example report or our guide on what is in a feasibility report.
Solar feasibility study vs feasibility screening
The terms overlap, but the depth differs. A solar feasibility study is the full assessment — a 29-page dossier with a 25-year financial model, zone-by-zone layout, and four engineering flags. Feasibility screening is the lighter first pass: a written pursue-or-park verdict, panel placement, and monthly generation profile on one building.
Screening answers "is this worth studying properly?"; the study answers "should we commit capital?". Most estates teams start with free screening, then commission the full study on buildings that pass. For scope detail, see what a solar feasibility study is.
Independent vs installer-led feasibility
Most free feasibility on UK commercial rooftops is produced by installers whose income depends on a proceed decision. That work can be useful once you have decided to go ahead — but it is a weak basis for the decision itself, because nobody is paid to say no.
An independent feasibility study is paid the same for a pursue or park verdict, shows its workings, and can be put in front of a board without a vendor's margin behind the numbers. Read the comparison in feasibility study vs installer quote, or use our checklist to validate an installer quote you already hold.
How it differs from an installer quote
An installer quote tells you what they will sell you and at what price. A feasibility study tells you whether the project is worth pursuing at all — with workings you can challenge and evidence you can put in a board paper.
Installer visits, drone surveys, and structural engineer appointments typically cost hundreds or thousands of pounds per site before anyone has tested the headline numbers. A feasibility study front-loads that test for a fixed fee. Read more: feasibility study vs installer quote.
Cost and turnaround
The full feasibility dossier is £1,250 per site, delivered in five working days. Priority delivery in two working days is £1,750. Same document either way. Fixed fee, written terms before work starts.
Free screening on one building costs nothing and arrives within three working days. See pricing detail or feasibility study cost in the UK.
Methodology and limits
Every dossier is independent, human-reviewed, and prepared to a documented standard. Built from satellite and metered data, validated against twelve months of metered output from an operating commercial installation.
Stage1Energy is a feasibility screening, not a precision measurement. We aim for an answer accurate enough to make a confident pursue-or-park decision — typically within ±15% — with every material figure validated against real data (our benchmark case sat within ±10% of twelve months of metered output). Exact yield and returns are confirmed at survey and design stage. Structural and wind outputs are screening flags requiring verification by appropriately qualified professionals. Our approach: methodology page.