Site assessment · Fixed fee · UK commercial roofs
Commercial solar feasibility study for UK commercial roofs
A written pursue-or-park verdict, 25-year financials, and engineering flags — shown on a real worked example below, so you can judge the depth before you spend £1,250.
What is a commercial solar feasibility study? An early-stage, desk-based test of whether rooftop PV is worth pursuing on a specific building. Unlike an installer quote, it is independent, fully sourced, and designed for a board or asset manager to read. Stage1Energy delivers the dossier in five working days for a fixed fee of £1,250 per site. Read what a feasibility study covers, our full guide, or explore the worked example before you book.
Real assessment · Commercial site, Greater London · Or start with free screening →
What it answers
Four questions, before survey spend.
Each answer is stated plainly, then traced back to its formula and source. Nothing arrives as a bare number. Every dossier is reviewed before release.
How much would it generate?
Hour-by-hour yield across a full typical weather year, per roof zone, with the seasonal shape shown month by month.
Named irradiance sources · published methodsWhat would it return?
A 25-year discounted cashflow: NPV, IRR, payback year, and the year-one cash drivers behind them.
HM Treasury Green Book discountingWhat could stop it?
Wind uplift, structural load, grid connection, and planning route — screened and flagged with a named next step for each.
BS EN 1991-1-4 · MCS 012 · ENA G98/G99Where do the numbers come from?
Sourced calculation workings run through the back of the document. Formula, result, source — for every figure that matters, line by line.
Engineer-readable · reviewed before releaseFrom address to dossier
You name the roof. Five working days later, this arrives.
Scroll to see how a site address becomes a board-ready verdict — then explore the live figures below.
Site verdict
Strong investment
Monthly generation
25-year cashflow
Inside the figures
Same worked example. Explore the figures.
01 · Verdict
Strong investment.
The dossier opens with a written pursue-or-park verdict: Strong investment on a 335.8 kWp system producing 304,070 kWh per year. The executive summary states 25-year NPV of £565,164 at a 7% discount rate and annual CO₂ avoidance of 70.8 tonnes. This section is designed for a board reader who needs the answer before the evidence — the rest of the 29-page dossier supports each headline figure with sourced workings.
Site verdict
Strong investment
pursue with confidence
System size
335.8
kWp installed
Annual yield
304,070
kWh / year
25-yr NPV
£565,164
discounted at 7%
CO₂ avoided
70.8
tonnes / year
02 · Money
£244k in. Break-even year 4.5.
The financial case models £244,015 capex against 25 years of import savings and export revenue. Simple payback occurs in year 4.5; discounted cumulative cashflow reaches +£565,164 by year 25. Year one net benefit is £60,948, split between import saving (£38,289), export (£25,098), and O&M (£2,440). Tariff escalation, panel degradation, and inverter replacement are included — not a single-year snapshot.
25-year discounted cumulative cashflow · 7% discount
Year one
Payback
03 · Roof
Four zones. One excluded.
The roof layout section shows panel placement on annotated satellite imagery. Four zones are modelled with setbacks and obstruction buffers; one zone is excluded with a stated reason. Zones are ranked by annual yield so the reader can see which roof faces drive most of the generation.
Ranked by annual yield
04 · Energy
304,070 kWh / year.
The energy profile section shows monthly generation across the year — from 7,005 kWh in December to 42,292 kWh in July on this example site. Self-consumption is 45% (136,748 kWh) and export 55% (167,322 kWh), matched hour by hour to the site's load profile rather than assumed.
Self-use vs export
Monthly generation · worked example
25-year generation
Annual yield with 0.5% / year panel degradation
05 · Risks
Four flags, screened early.
The engineering section screens four risks before survey spend: wind uplift, structural load, DNO/G99 grid connection route, and planning permitted development. Each flag states the screening outcome and the next step if professional verification is needed.
Inside the document
Eight of the twenty-nine pages.
Sample pages from a real assessment of a commercial site in Greater London. Feasibility sample — not for construction issue.
Satellite layout
Annotated satellite imagery with roof zones, panel placement, setbacks, and obstruction buffers — so you can see which faces drive generation before survey spend.
Executive summary
Board-readable decision summary: system size, annual yield, payback, NPV, and the pursue-or-park recommendation stated plainly before the detailed evidence.
Site verdict
Written site verdict with headline KPIs — on this worked example, Strong investment on a 335.8 kWp system producing 304,070 kWh per year and 25-year NPV of £565,164.
Financial case
Models £244,015 capex against 25 years of import savings and export revenue, with break-even in year 4.5 and discounted NPV of £565,164 at 7%.
Energy profile
Monthly generation across the year — from 7,005 kWh in December to 42,292 kWh in July on this example — with self-consumption and export split hour by hour against load.
Engineering flags
Four early screening flags — wind uplift, structural load, DNO/G99 grid connection, and planning — each with severity and a named next step before survey spend.
Sourced workings
Formula, result, and source for every material figure — so a board, adviser, or engineer can challenge assumptions rather than accept bare numbers.
Important notice
Scope and limits in plain language: feasibility for investment screening, not design, procurement, or construction documents — formal sign-off sits with qualified professionals.
What arrives
The dossier, section by section.
How it runs
Address in. Dossier out. Five working days.
One roof or a portfolio — each assessment is prepared with care and reviewed before release. Same standard at any scale.
01
You name the roof
Site address or a pin, plus anything you know about consumption. No site visit is needed to start. List as many buildings as you need.
02
The assessment is prepared
Roof geometry, yield, financial case, and engineering flags are built for your building — with every material figure tied to its source.
03
Reviewed before release
Results are checked, conflicts queried, and the dossier assembled with its sourced workings. Nothing leaves without that review.
04
You get the document
A PDF you can put in front of a board, an adviser, or a lender. Yours to circulate. Assessments are booked in order of receipt.
This is early-stage feasibility, not design or certification. Generation figures have been checked against twelve months of metered output from an operating commercial installation. Structural and wind outputs require verification by a chartered engineer.
Questions
FAQ
What is a commercial solar feasibility study?
A desk-based assessment of whether rooftop PV is worth pursuing on a UK commercial building — yield, 25-year financials, engineering screening flags, and a written pursue-or-park verdict. Not detailed design or an installer quote.
What is in the dossier?
A 29-page document: verdict, 25-year financials, annotated satellite layout, four engineering flags, and fully sourced calculation workings. Reviewed before release. Feasibility dossier for pursue-or-park decisions — not detailed design.
How much does a feasibility study cost?
£1,250 per site for standard delivery in 5 working days. Priority delivery in 2 working days is £1,750. Fixed fee with written terms before work starts. Or start with a free screening. See pricing.
Do I need a site visit?
No site visit is required to start. Send the site address and any consumption data you have. The assessment uses satellite imagery and published engineering methods.
Is the worked example a real assessment?
Yes — a real assessment of a real commercial building in Greater London, shown on this page so you can judge depth before spending £1,250.
Free screening vs full dossier?
Free: verdict, placement, monthly generation within 3 working days. Full: financials, flags, sourced calculation workings — reviewed before release.
Are the figures guaranteed?
No. Feasibility-grade figures for investment screening — not design or construction documents. Generation figures have been checked against twelve months of metered output from an operating commercial installation. Flags need professional verification.
Start here
Screen one building free first.
Pin the roof, send your details, and get a verdict, panel placement, and monthly generation within 3 working days — no card needed. When the roof is worth pursuing, we will confirm scope and invoice for the full dossier.
3 working days · No card needed · One building per request
Need the full 29-page dossier? Email us after screening, or read terms of engagement.