“Desk study” is the term UK estates teams and surveyors use for feasibility work done without setting foot on the roof — also called a desktop assessment in some briefs. Stage1Energy frames the same work as remote, evidence-based feasibility screening: data-driven analysis that decides whether a physical survey is worth commissioning. Surveys sit downstream; they are not a lighter/cheaper substitute for this stage, and this stage is not a lighter/cheaper survey.
For commercial solar, a desk study is usually the right first instrument: it takes days rather than weeks and answers the only question that matters at the start — is this roof worth pursuing?
This guide explains what a commercial solar desk study draws on, how far its conclusions can be trusted, and the point at which desk work must hand over to people on the roof.
What a solar desk study draws on
A properly built desk study is not a guess from a satellite photo. It combines:
- Aerial and satellite imagery — roof geometry, orientation, plant and skylight positions, access constraints, and obstructions that shade panels.
- Irradiance datasets — long-run solar resource data for the specific location, not a national average.
- Your consumption data — half-hourly meter data where available, letting generation be matched to load hour by hour. This drives the self-consumption split that usually decides UK commercial viability.
- Engineering screening — uplift screening by roof zone, indicative structural dead-load triage, preliminary DNO connection route (G98/G99), and permitted development criteria (TCP(GPDO) 2015 Class A/J — indicative, verify with the local planning authority).
- Roof plans and building information — where you can supply them, they resolve ambiguities imagery cannot.
From these inputs the study produces a concept layout, an hourly generation model, a 25-year financial case, and screening flags — the same core outputs as any commercial solar feasibility study, because a remote desk study is how feasibility at this stage is done.
How accurate is remote desk study assessment?
Built from satellite and metered data. Compared against twelve months of metered output from operating commercial rooftop PV.
Stage1Energy is a feasibility screening, not a precision measurement. Generation is modelled at P50 with a site-specific P90. CAPEX is quoted as a band, not a point — a firm installer quote replaces it. Returns are shown across that band, and the report states whether the recommendation changes across it. The detail is covered in how accurate solar generation estimates are.
What separates a credible desk study from an optimistic one:
- Exclusion discipline. Setbacks, plant, fire routes, and shaded zones removed from the layout, not painted over with panels.
- Loss stacking. Soiling, temperature, inverter, and availability losses applied explicitly rather than absorbed into a headline figure.
- Conservative export pricing. Export income discounted to realistic rates instead of subsidising a weak payback.
- Stated uncertainty. Where inputs are weak — estimated load, ambiguous roof construction — the study says so and attaches conditions.
What a desk study cannot do
The limits are real, and a good desk study names them rather than hiding them:
- It screens structural capacity; it cannot certify it. Roofs that pass feasibility still need a structural engineer before design — see feasibility vs structural survey.
- It cannot inspect roof covering condition, fixings, or corrosion up close.
- It cannot confirm DNO connection terms — it identifies the likely route (G98 or G99) and flags where export limits may bite, but the application itself comes later.
- It is not detailed design or procurement documentation.
In other words: remote feasibility decides whether the next tranche of spend is justified. It does not replace that spend.
Desk study, screening, and the full report
At Stage1Energy the remote method is delivered at two depths. Waiting list gives a written verdict, panel placement, and monthly generation profile on one building in three working days. The full feasibility report — available via the waiting list, five working days — adds the 25-year financial model, zone-by-zone layout, four engineering flags, and sourced workings for every material figure. Both are evidence-based desk studies; the difference is depth and evidential weight. The example report shows exactly what the full report contains.
When to commission one
Commission a desk study when solar is on the agenda but before anyone books a survey, files a DNO application, or invites installer tenders. That sequencing — remote feasibility first, physical work second — is what keeps UK commercial solar programmes disciplined and easy to defend. Timing guidance is in when to order a solar feasibility study.
If you have a building in mind, waiting list is the zero-cost way to start: name the roof, and a written verdict arrives within three working days.