Independent · Documented · Reviewed before release
Feasibility you can put in front of a board.
Every Stage1Energy dossier is independent, fixed-scope, and reviewed before release — whether you book one roof or a portfolio of 80+. Assumptions are recorded in the report, not buried in a spreadsheet. Built from satellite and metered data, validated against twelve months of metered output from an operating commercial installation.
What every dossier answers
From roof geometry to a 25-year cashflow.
Six stages, each producing a decision-ready output. The same standard applies at any scale.
Roof & layout
Roof zones are drawn from satellite imagery. Panels are placed within each zone after setbacks and obstruction buffers, honouring tilt and orientation per roof face. Flat zones are assessed for the layout that yields the most usable energy.
Solar yield
Site-specific annual and monthly generation from UK-validated weather data for your postcode. Irradiance is applied to each roof plane so the yield reflects your building, not a regional average.
System performance
Hour-by-hour output modelling with standard loss treatment for wiring, inverter, and soiling. Performance is calculated across the full year, not from a single peak-sun-hours shortcut.
Load & savings
Generation is matched against your consumption profile hour by hour where data allows — not a flat self-use percentage. The split drives both the import saving and the export revenue line.
Financial case
A 25-year cashflow with capex, operating costs, tariff escalation, degradation, and equipment replacement. NPV, IRR, payback, and LCOE are solved from stated assumptions you can challenge.
Engineering screening
Four flags — wind, structure, grid connection, and planning — each with a severity rating and a named next step. Screening catches issues early, before you spend on surveys or detailed design.
Every dossier is reviewed before release. Material figures are sourced and traceable in your report.
Quality & independence
What you can rely on.
Human review
Every dossier is checked before release — one site or many. A written pursue-or-park verdict, not a raw export.
Independence
We do not install, procure, or design systems. Our only product is an independent feasibility assessment.
Validation
Built from satellite and metered data, validated against twelve months of metered output from an operating commercial installation.
Sourced figures
Material numbers trace to named sources in your dossier. Defaults are stated, not hidden.
Fixed fee
£1,250 per site with written terms published before any paid work starts. No scope creep.
Recommend-against
We will publish the proportion of assessments we recommended against — see about.
Applied assumptions
Assumptions are recorded in every dossier.
Defaults are chosen for UK commercial feasibility. Exact values and sources appear on the dossier assumptions page — not summarised here. Every default can be overridden with real data from your site: bills, quoted tariffs, a firm grid quote.
Categories recorded in your report
- Analysis life
- Discount rate
- Panel degradation
- System losses
- O&M costs & escalation
- Tariff escalation
- Carbon intensity
See the assumptions page in the worked example.
Where feasibility stops
Stated limits, not small print.
This is early-stage feasibility, not a design tool and not certification. We state what the assessment does not cover so you know what further work may be needed.
Near-field shading
Terrain horizon shading is in the satellite data. Trees, adjacent buildings, and roof clutter are not modelled — they need eyes on site.
Setbacks
Perimeter setbacks use a geometric minimum. Real fire, access, and fall-protection setbacks are larger and reduce panel count.
Structural & wind
Both are screenings against typical allowances. A chartered engineer must verify before any commitment to works.
Costs & tariffs
CAPEX uses published cost bands, not your installer's quote. Grid works carry a default allowance until the DNO responds.
Accuracy band
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. Remote, evidence-based feasibility decides whether a physical survey is worth commissioning; surveys are downstream, not a quality competitor.
Not design
Outputs are not procurement, construction, or MCS design documents. They answer whether to pursue — before you spend on surveys and detailed design.
Annual kWh is the decision metric; monthly figures show seasonality. See it applied in the worked example.
See the standard before you commit budget.
Screen one building free, or explore the worked example dossier.
No card needed for screening · Clear go or no-go guarantee in our terms of engagement