A commercial solar feasibility study sits at the front of a sensible rooftop PV process. Before anyone climbs on the roof, before a structural engineer produces calculations, and before an installer prices a system they have not yet designed, feasibility answers a simpler question: is this roof worth pursuing?
That question sounds straightforward, but in practice it spans generation potential, self-consumption economics, grid connection constraints, structural and wind-loading flags, and planning risk. A well-run study pulls those threads together and ends with a clear recommendation — pursue, pursue with conditions, or do not pursue — so decision-makers are not left interpreting spreadsheets and satellite images on their own.
Why feasibility exists as a distinct step
Commercial rooftop solar in the UK rarely fails because the technology does not work. It fails because the business case was never properly tested, because a constraint was discovered too late, or because an optimistic quote was mistaken for independent analysis.
Feasibility exists to close that gap. It is deliberately earlier and lighter than design, procurement, or construction documentation. The commercial solar feasibility service at Stage1Energy is built around that principle: give estates and asset teams enough rigour to make a go or no-go decision without paying for work that only makes sense once the case is proven.
Think of it as the equivalent of a pre-planning opinion for a development site. You are not submitting a full planning application; you are testing whether one is likely to succeed.
What a feasibility study typically covers
Scope varies by provider, but a credible commercial rooftop feasibility study should address the following areas at screening level.
Roof resource and layout. Usable area, orientation, pitch, shading, and a sensible estimated array capacity based on what the roof can physically accommodate — not what an installer hopes to sell.
Generation and consumption. Annual kWh yield, typically modelled with recognised methods, plus self-consumption versus export assumptions tied to your actual or estimated load profile.
Financial outcomes. Payback, net present value, and a multi-year cashflow view using defensible tariff and cost assumptions. These are feasibility-grade figures for decision-making, not audited investment advice.
Engineering flags. Screening-level notes on structure, wind loading, roof condition, access, and mounting approach — enough to know whether a full structural survey is likely to be straightforward or contentious.
Grid and planning. Whether the connection is likely to fall under G98 or G99, whether export limits may bind, and whether permitted development or a planning application is the probable route.
Verdict. A written conclusion that a board, investment committee, or client can act on.
For a detailed breakdown of each section, see what is in a solar feasibility report. You can also review the structure in our example report.
What a feasibility study is not
Clarity about boundaries prevents expensive misunderstandings.
A feasibility study is not a structural calculation pack. It may flag that a portal frame needs checking or that ballast loading looks tight, but it does not replace a structural engineer’s sign-off.
It is not a detailed electrical design. Cable routes, protection coordination, and as-built single-line diagrams come later.
It is not an installer quote. Quotes assume a viable project and embed commercial incentives that feasibility deliberately avoids. The difference matters; we cover it in feasibility study vs installer quote.
It is not a guarantee of performance. Generation figures have been checked against twelve months of metered output from an operating commercial installation. Generation estimates are feasibility-grade and should be read in that context. Our methodology explains how Stage1Energy approaches modelling and where uncertainty remains.
When feasibility is the right move
Feasibility pays off when you have one or more candidate roofs and limited time to separate winners from dead ends. Typical triggers include a net-zero target with an unconstrained estate list, a landlord considering PV across a portfolio, a developer testing solar on a speculative unit, or a facilities team asked to “look into solar” without a defined budget for surveys.
If you are unsure whether a site clears the first hurdle, free screening is the lighter entry point: a short verdict in three working days. When you need the full financial model, engineering flags, and board-ready dossier, the site assessment delivers a fixed-fee feasibility report in five working days.
How Stage1Energy fits the process
Stage1Energy produces fixed-fee feasibility dossiers for UK commercial rooftops at £1,250 per site, with a written scope and human review before release. The same document works for a single warehouse or a batch of sites assessed in parallel — useful when you are comparing opportunities rather than anchoring on one address.
The output is designed for internal decision-making: enough depth to justify spend on structural and grid work, not so much detail that you have paid for design before you have decided to proceed.
Bringing it together
A commercial solar feasibility study is the disciplined first step that stops weak projects absorbing budget and lets strong ones move faster with confidence. It translates roof geometry, consumption patterns, and regulatory constraints into a single narrative a decision-maker can use.
If you are commissioning one, insist on independence, transparent assumptions, explicit limits of what the study does not cover, and a verdict you can put in front of a board without rewriting it. That is what feasibility is for — and nothing more complicated than that.
How feasibility fits UK building types
The same feasibility framework applies across warehouses, factories, retail sheds, and offices, but the emphasis shifts. A logistics depot feasibility leans heavily on high daytime load and large unobstructed roof area. A multi-let office may hinge on landlord consent, tenant electricity arrangements, and a lower self-consumption share. A manufacturing site with shift patterns outside standard daylight hours needs honest load profiling rather than generic benchmarks.
Good feasibility authors adjust narrative emphasis without changing core methodology. The dossier should still end with the same clear verdict structure whether the roof is in Manchester or Cardiff, owner-occupied or landlord-held. That consistency is what makes feasibility useful when you are comparing unlike buildings within one portfolio programme.