By the PPA Funding team Last updated
A solar feasibility study is the assessment carried out before a commercial system is designed. It checks the roof or ground, structural strength, shading, your electricity usage and the grid connection, then reports how much solar the site can take, likely output, and whether a PPA or purchase stacks up.
What does a feasibility survey actually check?
The survey starts with the roof or ground area: its size, orientation, pitch, and condition. A structural check confirms the roof can carry the extra load, or that ground conditions suit a mounting frame. The surveyor also maps shading from chimneys, plant, trees or neighbouring buildings across the day and seasons.
Alongside the physical checks, the study reviews your electricity use, ideally from half-hourly data, to see when you draw power and how much solar you would use on site rather than export. It also flags whether the roof needs repair before panels go on, since removing them later is costly.
Why does the grid connection get checked so early?
The local network operator sets a limit on how much generation a site can connect and export. The study estimates the system size against that limit and flags whether a G99 application or an export limit is needed. Getting this wrong late in a project causes delays and redesign.
Where the site already has a heavy supply, such as three-phase, there is usually more headroom for a larger array. The feasibility report gives you an early read on connection risk before any money is committed.
What does the finished feasibility report tell you?
A good report states a recommended system size in kWp, an estimated annual output in kWh, the share you would use on site, and an indication of savings. It should also note structural findings, shading losses, and any grid constraints, so you can judge the project on evidence rather than a sales pitch.
Under a PPA the funder usually commissions and pays for this work, because they carry the performance risk. Treat the numbers as estimates, and ask how output was modelled. Confirm any tax or accounting assumptions in the report with your accountant.
This guide is general information, not financial or tax advice. Your circumstances determine what applies — please confirm with your accountant or advisor. Get a tailored proposal →
Frequently asked questions
How long does a solar feasibility study take?
A desktop review can be turned around in days, using satellite imagery, your usage data and network records. A physical roof and structural survey adds time, and grid checks depend on the network operator's response. For most commercial sites the full picture takes a few weeks.
Do I have to pay for a feasibility study?
Not usually under a PPA. Because the funder owns the system and carries the output risk, they typically fund the survey and design. If you buy the system outright, the study cost normally sits within the project. Ask the provider who pays before work begins.
Related guides
- Solar Panel Recycling and End of Life: What Happens to Commercial Panels
- Rent Your Roof for Solar: How Building Owners Earn From Unused Roof Space
- On-Balance-Sheet vs Off-Balance-Sheet Solar: How the Funding Route Shows in Your Accounts
See our funding options, commercial solar and solar by industry pages.